Just my quick opinions:
1) Built in HD, which some people bemoan, is actuallly a HUGE step. Ever since MDs hit the market, people have been clamouring for a PDA/cellphone with a built in MD. It's the first PDA to ever have a built in drive, which opens up the possibilties (hence, little flash memory necessary). Some think that it sucks batteries, but the newer MDs do not consume appreciably more juice than regular CF. However, spinup/spindown time might become an issue. Either way, this is a big marketing bullet - which alone might get them a significant amount of sales. BTW, I wouldnt worry too much about the MD dying - it should be fairly trivial to replace it with not much more than a small screwdriver and patience. I do agree with the other poster that it would be amazing if it were easily changeable (imagine that).
2) Non-lighted keyboard? WTF? This is the fourth gen unit and STILL no backlit keys?!?!?! ARGH.
3) Biggest dissapointment - why is it still the old 3.7" screen? The housing would have easily fit the SL6000 4" screen!! ARGH. If this isn't transflective, there's gonna be hell to pay.
4) No wifi/bt - they clearly didnt want to commit to either, and chose to address memory. This is a quite a cop-out as there are many single chip/dual radio solutions on the market nowadays. Both Sony and Dell have done it - why can't Sharp? I think "Didnt want to" might be the answer.
5) I really think 64mb ram could have easily been 128mb with little to no change in price. Sheesh, ram is dirt cheap. However this may be moot, given that no _built in apps_ ever get close to maxing out this usage.
6) I swear to ghod, that if Sharp left all that empty space underneath the unit (the big battery cover), they should be taken out back and shot! That space could easily have housed a large antenna, or another CF, or etc.etc.etc.
7) Ashikase indicated that the EA-BL11 1800mah battery might fit the C-xxx units. This alone might be the best thing to come out of this whole launch.

I do like the new directional pad though - this should have been how it was done in the first place. However, why shrink the size of the app keys and not use the extra space to make the keyboard buttons larger?! As it stands, the app keys are just harder to press...
IMO, Sharp's PDA department is showing clear signs of having their funding cut. This unit bears the look of many compromises.
Yz