i did this swap a few weeks ago. although the processor is .2 GHz slower, you won't notice. also the screen clarity and sharpness was a concern since it's the same pixels spread onto a larger screen, but i don't notice any graininess. display render appears more detailed and colors are still vibrant. screen can be really bright. it took some time getting used to the 4 click keys at the bottom since i was used to just touching them on the d2g, it's the only annoying feel i've experienced so far, because the keys are not soft touch or integrated into the screen, so more effort goes into pressing a key when you're using the device with one hand.
with the latest gingerbread version 591, i enjoy using the dx more than i did the d2g. camera resolution is better, and with the extended battery i can get a full 1.5 days out of it when i can't get to a charger.
overall, it's a nice phone, i wouldn't go back.
