There are lower end models that use mesh heads too. One thing I'd caution though it to determine whether the MIDI it outputs is configured properly. The issue is that many brains can't configure the MIDI values - in that case you need to have one that matches the expected set of values.
Something like
http://docsrockbandmods.netforums.us/ is a probably a good place to go. I'm sure they'll start compiling a list of known compatible devices if they haven't already (I know the MIDI values have been posted somewhere there too).
As for the Ions, yeah a friend of mind has it. It's definitely a huge step up from the game drums - it is an actual (low end) e-kit. The main advantages are better durability, and most importantly, placement configurability. That importance of the latter cannot be overstated. Getting your kit set up for your body makes drumming sooooooo much easier. You should definitely get an adjustable drum throne too - seating height is very important, particularly for pedal work.
What isn't a huge step up is the feel though. The pads are a bit more cushiony (and thankfully quieter), but your still hitting a hard surface with little give. It doesn't feel like a real drum, both in terms of physical touch but also in the fact you do not receive the proper kinetic feedback. The bounce of a real skin (or mesh head for the most part) makes it much easier to do rolls consistently, transitions, etc.
If you want more details about what makes my specific kit better, I can give them. It might be better to find some in your price range and then ask questions though. I'll simply say that their is little comparison between the Ion and my set