Now you made me laugh... Kinda ironic for me, but there are reasons why I always return to stock. I have tested about 7 different roms, 7 different kernels, 15 modems and combinations thereof and for me the following worked:
GB: CheckROM based in XWLA4 with ICS Domination (+ mods) and JKay deluxe - Siyah kernel (the one that came with CR) - whatever modem for SA at the time
ICS: Stock XXLPD with ICS Domination (+ mods) and JKay deluxe - Speedmod kernel - LPS modem
JB: NeatROM Lite 4.0 with mods - Siyah kernel - LS6 modem
Apart from stock, my favourite roms in order are Resurrection Remix, CyanogenMod and NeatROM (others not worth mentioning as far as my preferences are concerned)
Best kernel ever and by far is Siyah. GM develops and doesn't only cherry pick cool features from other kernels without proper testing.
EDIT: Oh yes... And I kept 58 stable nandroid backups. Did probably close to 80. That is a lot of flashing considering I had my S2 since 11-2011
Now that is interesting...
I have gone through about 10 or 12 ROM's (off the top of my head) about 6 kernels (not kernel versions- that must be about 15 then) but oddly only 4 modems that I can recall. Have tried it all from Samsung based, through to MIUI, AOSP, AOKP and even Boot2Gecko.
The best combos I had were:
GB: Stock rooted (didn't use GB for long).
ICS: Close call between AdyScorpius MIUI v4 with Siyah kernel and LPS modem and FoxHound ROM with Siyah kernel and LPS modem.
JB: Resurrection Remix 3.1.3 with Siyah v5 vsync and LPS modem.
Apart from the AOSP / AOKP ROM's, my favourites for a while were MIUI based ROMS. Never was a fan of stock ROM's, but the JB test ROM has worked flawlessly and I really do like it.
Agreed on Siyah being the best kernel- have never had a single issue using it, across all the CM9/10/AOSP/AOKP/MIUI ROM's that I have flashed. Will be a sad day indeed when GM stops development for it completely
I have not made even half as many nandroid's, because early on I didn't really care... Until I lost root and then lost everything in trying to fix it. Now I make a backup before every single zip that I flash. I have kept about 3 backups in total, just in case I want to go back and experience other setups.
On a side note- the jig works on JB, used it last night when I flashed the TAR of Siyah v6 onto the JB test ROM.