1. 32MB Rom compared to 48MB Rom of the Axim
The AsusBT has 64 mb ROM. However, it costs a bit more

. Who cares though? You said yourself that you have a few 512 mb memcards; I doubt any program will require more than 32 mb memory.
2. No SD Card slot (Although I don;t have any SD accessories, I still like to know it's there)
3. No removable battery like the AXIM which means I can't buy any extended batteries like the 3400mAH Battery...
The Asus has a HUGE battery length. Look at for an impressive display of its battery length. To quote:
"The first type of test is what I consider the torture test. I set both of the devices at a comparable backlight level, the Asus at level 20, and the 2215 on its sixth notch. I then set the sound on both of the units to the second notch from the bottom, and ran them both at their standard 400mhz settings. I looped a full length movie (Boondock Saints, great movie) over and over until the battery ran down to 0%. I ran the movie off of a 512mb CF card for both devices.
Device
Time until device hit 0% battery
Asus A620
4 hours 25 minutes
HP 2215
4 hours 52 minutes
The Second test I ran is a bit more laid back, I set the backlight levels the same as before, and set the devices with only Battery Monitor running until they reached 0%. Not exactly a strenuous activity, but it gives you a fair estimate of how it would last using only the built in PIM functions. In the screenshots below, don?t be fooled by looking at just the ?running? time, you must subtract the ?suspend? time to get the actual time that the device was on.
Device
Time until device hit 0% battery
Asus A620
13 hours 5 minutes
HP 2215
11 hours 20 minutes
Hope that helps.
~Neszis~