Alright, most of you must already be familiar with usb loader x360key.. Let us get acquainted with current available options. 
This thread is created because I'm dumbstruck between x360key and wasabi 360 usb loaders... And of course, to confuse you all equally
Wasabi Pros over x360key:
[strike]1. Can load games with xbox controller and gui, xkey used it's own wired remote for this.[/strike] (Feature added by x360key as well via firmware update)
2. Little bit cheaper.
3. Integrated extension to xbox enclosure, looks neat.
x360key Pros over Wasabi:
1. USB2.0 instead of eSATA (eSATA is much faster but user is limited to using only HDDs..adds to expense with eSATA enclosure)
Alternatives:
x360dock:
1. Much cheaper... almost 60% of cost of x360key
But requires a computer to load ISO that are available on the HDDs that are mounted in this PC.
it is more like a split x360key in 2 parts:
I. The ODDE board that sits in the xbob and other part is
II. Remote - This can be purchased separately if you want to load from usb without PC.
Costs a little above x360key if both purchased separately, no clues about a combo deal as 2nd batch is yet to be released; Thus i'm not considering this.
x360dock is a good option for people who have MediaCenter PC or download rigs, you and save around $60 by avoiding investing in extra remote.
Your ISO will be stored on the connected PC and thus you can avoid an external device being connected to your xbox directly...Less clutter.
Boxzii:
Yet to cover this one, will update thread when i'm done.. time for lunch
Approximate Prices:
Wasabi360: ~$99
x360key: ~$99-115
x360dock: ~$65-70
Boxzii: ~$70-115
Complete features as per manufacturer websites:
PS: Mods, this guide suites this section better, thus posted here; you can move if it is not appropriate.
PPS: Guide is being edited as and when new information is available. Feel free to post or PM me incase you want me to feature similar products and or modify/correct those that are featured.

This thread is created because I'm dumbstruck between x360key and wasabi 360 usb loaders... And of course, to confuse you all equally

Wasabi Pros over x360key:
[strike]1. Can load games with xbox controller and gui, xkey used it's own wired remote for this.[/strike] (Feature added by x360key as well via firmware update)
2. Little bit cheaper.
3. Integrated extension to xbox enclosure, looks neat.
x360key Pros over Wasabi:
1. USB2.0 instead of eSATA (eSATA is much faster but user is limited to using only HDDs..adds to expense with eSATA enclosure)
Alternatives:
x360dock:
1. Much cheaper... almost 60% of cost of x360key
But requires a computer to load ISO that are available on the HDDs that are mounted in this PC.
it is more like a split x360key in 2 parts:
I. The ODDE board that sits in the xbob and other part is
II. Remote - This can be purchased separately if you want to load from usb without PC.
Costs a little above x360key if both purchased separately, no clues about a combo deal as 2nd batch is yet to be released; Thus i'm not considering this.
x360dock is a good option for people who have MediaCenter PC or download rigs, you and save around $60 by avoiding investing in extra remote.
Your ISO will be stored on the connected PC and thus you can avoid an external device being connected to your xbox directly...Less clutter.
Boxzii:
Yet to cover this one, will update thread when i'm done.. time for lunch

Approximate Prices:
Wasabi360: ~$99
x360key: ~$99-115
x360dock: ~$65-70
Boxzii: ~$70-115
Complete features as per manufacturer websites:
Wasabi360 said:• Unique, intuitive on-screen user interface - navigate the ISO list directly from the Xbox 360 dashboard using your controller. No need to interact with a small remote/LCD for feedback or navigation. No need to ever leave the sofa. See the demonstration video!
• Solderless installation
• Support for XGD3 games
• Support for AP25 protected games, without needing to patch ISO's
• ESATA interface is used in place of USB providing superior performance, since data is transferred directly between the ESATA HDD and Xbox 360 resulting in impressively high bandwidth, many times faster than reading from a real DVD disc. See our speed comparison!
• Elegant and streamlined console inspired case design
• Versions available for both fat and slim consoles
• NTFS file system natively supported
• Multi-disc games fully supported
• Powerful embedded CPU running performance tuned Real Time Operating System
• Regular firmware updates available free for download
• Fully updatable hardware (MCU and FPGA's) from ESATA HDD including a failsafe recovery mode
• No need to flash or in any way modify your original ODD
• Hardware selectable pass through mode – allowing games to be played from the original disc drive in a 100% Xbox Live safe manner
• Latest supported Xbox 360 dashboard version: 2.0.13604.0
Features to be added in future firmware updates:
• Automatic extraction of the DVD key
• Xbox Live compatibility
• Dumping of X360 ISO's from original discs
Wasabi 360 - Product
x360key said:
- User friendly: intuitive interface, no soldering required
- Compatible with both Fat and Slim models
- Supports most Xbox 360 and Xbox 1 games
- Supports most file systems, including NTFS, EXT2/3/4, and Mac OS X Extended
- High speed USB 2.0 interface
- Stylish USB control pad for selecting games and controlling your x360key
- Powerful embedded Linux system running from Micro SD card (included)
- Linux firmware fully updatable from USB media
- FPGA fully updatable from USB media via built-in, in-system JTAG programming
- Recovery mode - it is always possible to recover from a bad flash
- No drive flashing or JTAG hack required
- AP25 protection emulation
- Pass-through mode. (Use your Xbox 360 in "normal mode")
Features to be added in future firmware updates:
Loading games from NFS and Samba shares*
- Web Control Panel (Requires a wifi dongle that will be sold separately)
x360key features
- Xbox Live support
- Backup original Xbox 360 games to USB hard drive
x360dock said:Module 1 : Internal Mainboard + USB PC Control Dongle
• SAVE the cost of extra USB HDD or pendrive, Grab the backup Games directly from the PC HDD.
• Cleaning Games management platform based on PC only, No worry about the Xbox360 dash upgrading.
• User INTERFACE friendly, no soldering required
• Compatible with both Fat and Slim consoles
• Latest supported Xbox 360 version: 2.0.13604.0
• AP25 supported
• XGD3 supported
• Plug and Play/Requires DVD Key
• No need to flash or in any way modify your original DVD drive
• Avoid Overheating and >75% 3 Red lights of Death posibilites
• USB 2.0 and ULTRAFAST LOADINGS
• DVD/DL/Multigame compatible
• Full upgradeable by USB/JTAG, Regular firmware updates available free for download
• Drive mode–allow playing games from the DVD drive in a 100% Xbox Live safe manner
• Remote ISO selector by Iphone/IOS/Android systems (Requires WIFI)
Module 2 : X360dock motherboard package + External Full Color 2'2" TFT Touchscreen panel for USB HDD/Pen drive (No PC required)
• High speed ARM games management system
• Full Color 2'2" TFT Touchscreen
• Full Color touchscreen cover flow ISO/config selection system
• 3Ports USB 2.0 High Speed (480M/S) HUB embeded for USB HDD/Pen drive (No EXTRA Hub cost)
• NTFS File system supported
• USB / SD upgrades for FPGA and Microcontroller system
• External SD socket (No needed disassembly if SD card replacement required)
• Full clean installation / Place the module 2 where ever you want
• Easy Installation/Just need plug USB cable from X360dock Module 1
Features to be added in future firmware updates:
• Automatic extraction of the DVD key (Not sure if it can be done ,but DockTeam never gives up)
• Xbox Live compatibility
• Dumping of X360 ISO's from original discsbr
Products - X360DOCK Official Site - WWW.X360DOCK.COM
PS: Mods, this guide suites this section better, thus posted here; you can move if it is not appropriate.
PPS: Guide is being edited as and when new information is available. Feel free to post or PM me incase you want me to feature similar products and or modify/correct those that are featured.