I just upgraded my D2500CC box with latest snapshot. Upgrade went just fine just one thing bothered me - my full backup was 15 GB, lol :)

I use Intel NICs and there were errors on 2.1 when I copied large file between 2 LAN interfaces.
Now it is faster and no more errors, probably thanks to new drivers for Intel.
Furthermore, ping for WAN reduced from 3ms to 1.7ms when idle :) yay :)

Whoever is experiencing strange things with Intel NICs, I strongly recommend to update.

Oh and OpenVPN works just fine, rules and NAT rules are OK, everything is OK actually.

Thanks!