A good start.
But lots of little niggles.
The B2 has no air intake for the front-mounted supply. The bottom is close to the floor and the way CM and all similar cases provide for air intake is by providing an intake grid below the supply, on the floor of the case. In this cabinet the user has to drill holes if he has a bottom-mounted fan on his supply (and all their own supplies do, some only have the bottom fan!).
The 3.5" drive cage can take 4 devices, of which only one is tool-less in the picture. If you have more drives, you're basically hosed unless there's hardware provided for the others - the rest of the drives have to be secured with bolts like any other case. On the good side, looks like the drives will stay cool with space between them and an intake right in front.
I don't know if it's the camera, but all the cases look very ugly with a terrible finish. Higher resolution shots or a live demo will tell how ugly or pretty they really are. As usual the company logo is the most garish element on the products - no sense of aesthetics or design.
Specifications are misleading. Cases are made with SECC steel, but the marketing lingo claims "Special heat absorbing and radiating material". There's nothing special about SECC. It's standard material to build cases with, and unless you're comparing it to biscuit tins which are used to make el-cheapo cases, one needn't flaunt it or try to cover it up in marketing speak.
The dual-chamber Cube case is really interesting, though. I'm not hot on the front of the case, it will need stickers to cover the fugly logos - again no sense of aesthetics. The inside looks good, may be able to execute a reasonably silent system with lots of fan control or well-planned ducting and airflow.
Lastly, the 'Hornet' and the 'Black Jack' Look like they'll have some issues with long graphic cards, as the ATX mounting holes are right up against the drive cage. The GTX as well as the upcoming 3870x2 are physically longer then the width of an ATX board, and they need an inch or so clear behind the board. Not sure they'll fit - or they may fit really tight with no room to spare. It doesn't help the pictures are so low resolution - zooming in destroys any chance of being able to tell if this is correct or wrong.
The keyboard and supplies look interesting. It will be interesting to see if Zebronics can get over their terrible reputation with power supplies with this series. There are many ways to get a high-output supply, and the units are not certified as far as I can see. UL, ATX 2.2 and/or 80Plus would add a lot of credibility to the power ratings, as most units in that power range do offer international certifications of some kind or the other. Users can choose what ratings mean more to them and make decisions accordingly. However at first blush the specs look quite beefy at the top end of the power range, and even the humble little 350 looks like a decent starter supply. It's all down to who actually manufactured the supply and how many, if any, shortcuts they took to achieve the high power outputs.
Good start by these guys hopefully they'll put a little more thought into their next wave of products, and hire a good design team to fix up their logos and general design.