So aside from the memory issue, why would I *not* want to get the TSU-3500? I currently have a TSU-2000, which is on its last legs, but has served me well for 5 years.

Memory is not a concern for me...4MB is huge. I use about 1 MB total across all of my devices.

I heard bad things about the 3000, so I figured I'd wait until the 3500 was available -- and it is. it seems to have everything I want...rechargeable battery, a dedicated joystick area, plenty of memory, better backlighting than the 3000, so what are the downsides?