If you have Macs and are also willing to get the OSX version of the program I'd recommend Bento. Unfortunately at this time the only way to sync the data back off the iPad version is thru the OSX version. There are benefits to having the combination; like being abel to sync and set up better reports than you could with just the iPad, so it's worth consideration if your device mix allows it.
From the same company, if you're willing to make the investment of money and time, the combination of Filemaker Pro for OSX and Filemaker Go for the iPad is an extremely flexible and powerful solution.
Otherwise I recommend looking at HanDBase. I don't use it, but it has decent reviews and is probably just as powerful (for a mobile app) as Bento. Just not as pretty or easy to setup.
