I have also just picked up a 3800 with multiregion and PAL-P, and it works like a dream so far. Have been testing random discs, and everything has worked, including RCE titles. For Region 2 PAL-P I tried Battle Royale SE and it had no problems. I'm afraid that's the only R2 disc I have, as it's not currently available in R1 as far as I can tell.
The picture is superb into my Panasonic plasma, and I can definitely notice a significant difference between it and my previous Toshiba SD9000 (interlaced). I guess the deinterlacing on the Denon is much better than my model 4 plasma. One of the main things I have been impressed with is that the picture is much less noisy than previously. I thought this was an issue with plasma technology but it is obviously not entirely so, as the picture from the Denon is much smoother than I have been used to. The sound also seems richer than previously, even though I am using the same Denon AVCA1SE amplifier. I didn't expect to hear much change in the sound, but I have to say I have been pleasantly surprised all round.
The discs are still pretty warm when they come, but haven't had any problems yet (only day one though). BTW, my serial number also starts with 2088.