No. In android when you install custom ROM you change the entire OS but here you just jailbreak (equivalent of rooting in android). After you jailbreak your device will have a new icon of CYDIA which is an alternate app store type where individual developers provided jalbreak apps / tweaks that might be useful to you and might give your phone additional functionality. Like a tweak called NCSettings will give you quick toggles for Wifi, 3G, EDGE, bluetooth, shut down phone etc, something which apple does not provide.
But remember one thing. If you iPad is in warranty then jailbreaking voids your warranty so in case something happens to your iPad in future (not because of jailbreak, it can be any reason), you will need to remove the jailbreak and then submit the iPad for warranty claim.
Also if your device is jailbroken NEVER EVER do the "Erase all content and settings", it will mess up your iPad big time and only method to recover will be to restore.