Naim Supernait 2 vs Supernait 3

there is a naim forum where you will have the best luck to find the answer to your query

Yes, the Naim forum is definitely the place, but I will say that the best thing you can do for any Naim component is to use the best outboard power supply they offer for the unit.  The differences are transformative. Really makes you aware of the effect a power supply has on a component. 

Based on folks on the Naim forum who have compared both, more people prefer the Supernait 3 over 2 while a few prefer the 2 over 3. The 3 was claimed to be slightly more clean and detailed than the 2. The 2 was said to have more weight and drive in the bass, more of the "typical" Naim sound.

There isn’t any consensus whether the Supernait 2 or 3 will sound better when used with the power supply (Hicap DR). Although there are few who prefer to use the Supernait without the power supply, there are many who run the Supernait with one.

The 3 has the built-in phonostage which will be useful to some people.

Thanks everyone for the replies!

Their are cheaper Power Supplies (TEDDY) that can be used on the NAIM gear with the same results.

new to the forum but I thought I'd chime in. didn't do an A/B with the sn2 but I did do an audition between an xs3 and a supernait 3 (speakers were proac d2r). The sn3 was better, better grip of the speakers and just sounded more confident. that's not to say I didn't like the xs3, it's still a cracking amp and there wasn't much in it. Personally I think it's hard to tell much difference when doing a quick A/B test, you really need to spend a long time with each. 

From speaking to the dealer, he thought the SN2 would still be better than a XS3 so I don't think there'd be much in it between the sn2 and sn3. although reading some of the comments on the naim forum suggest it's loads better. not sure if that helps.