Ok, had my D3 since Friday, here are my impressions so far:
1) Speed - love it. But I'm coming from an OG Droid, and no matter how overclocked the kernel (mine was at 1.25ghz) that old processor and skimpy RAM just crumbled under GB. D3 is fast, responsive, benchmarks like a mofo, all is well.
2) Screen - love it. Pentile or not, it's bright when it needs to be, colors are vibrant and accurate. I'm a colorist (do final color on motion pictures and commercials) so I'm very sensetive to this. I do wish the blacks were a little blacker, but short of that it's excellent. Haven't seen any of the jaggies with high-contrast edges or small white text, and I've looked pretty closely. Get close enough to just about any digital screen and you're going to see pixels eventually.
3) Motoblur - don't hate it. As a matter of fact, I'm growing to like it quite a bit. I have set it up just the way I like, and so far the experience is quite good. Coming from unskinned, custom roms on my rooted D1 I thought I'd really had the stock GB / motoblur, but that's definitely not the case. That said, by the time this baby gets a root exploit I'll probably be ready for change.
4) Battery - so far so good. Not the best battery life, but I'm using it obsessively(!), and getting nearly a full day per charge. A bit better than my D1 with ROMs that were very good with battery life. I imagine as I use the D3 more, and once custom kernels come out with better tuning, we'll see longer times between charges.
5) Speaker - it's functional, loud enough to hear rings in noisy environments. Seems very similar to my D1, maybe not quite as loud, but close.
6) Build quality - excellent. It feels great in the hand, the slider functions smoothly, solid without being stiff. The keyboard is an absolute pleasure, best I've ever used on any mobile device. I wish the volume buttons were just a tad larger, but they're still functional. I like the centered power button, since I'm ambidextrous and never know which hand I'll be hitting it with. My only real gripe is how the battery cover is held on. I really liked the OG Droid cover with its solid mechanics. The D3 cover snaps on, and while it's on securely, it just doesn't feel as solid.
7) Reception - excellent. No dropped calls yet, more consistent 3G reception in my spotty home area. I travel to Canada regularly, and plan on putting in a Rogers or somesuch SIM, will report on GSM radio when I get a chance to take it for a spin.
All in all I'm really pleased with the D3, it's a fabulous upgrade from D1.
cheers,
JT