Given your system, I would put the LP12 on a better support and change out the cartridge to a Dynavector. Or, if you want a set and forget type TT, go for the P9. From your system description, you have a need for speed. I have an LP12 and have not personally heard the other tables, but I think the other tables (except the P9) play up the hi-fi aspects of music (soundstage, even frequency response, detail retrieval, air etc) more, but do not quite have the musicality (i.e. PRAT) of the Rega and the Linn. The two biggest upgrades to my LP12 were the Mana wall shelf and the Dynavector 17D2 (which is why I suggested them). For more discussion on LP12s, I suggest going to the Naim site (www.naim-audio.com ?).
Mike
Mike