Naim Supernait vs Nait XS vs Nait 5i: Differences

I have read that the Supernait sounds close to the XS. Are there substantial sound differences between these three models? What are the expected improvements going from the Nait 5i to the XS, and the XS going to the Supernait? Apart from the additional features of an on-board DAC in the Supernait, does the unit have superior sonics compared to the Nait XS?

Any advice would be appreciated.
Check here:
I compared the 5i to the supernait and would have to say sonically they are quite close but since the supernait has more power so it can 'control' low efficient speakers better. Then added the flatcap power supply and the power/control jumped up a hair more. The speakers we used were the Dynaudio C2's. For its price point the 5i held its own pretty good. With the xs and supernait you can add the flatcap where with the 5i you can't.
Thanks all for your comments. Tried to access the Naim forum but membership still pending approval. Guess my application may have been rejected.
To paraphrase Groucho: I wouldn't join any forun that would take someone like me as a member.
I have owned all three. Unless you need the DAC in the Supernait, I would not recommend it over the Nait XS. That is my favorite. It has almost as much power. Supernait is more than twice the price of Nait XS at retail.

Having said that, The Nait 5i is pretty darn close at a much lower price. The Nait XS can take a power supply, Nait 5i cannot. Power supplies in the world of Naim are a big upgrade, worthwhile. Nait XS can power a Stageline phono preamp and it has a subwoofer output, Nait 5i cannot do either.

Can't go wrong with any of them. Naits are always great, no matter which one you choose.
I have compared the three at a local dealer, and bought the XS. It is quite a bit more detailed than the Nait 5i, with a lot more soundstage information and inner detail which the 5i misses. The 5i does have the characteristic Naim prat, and feels more powerful than its rated output, but less powerful than the XS.
I think that for a careful listener who likes the typical audiophile values such as transparency, detail, soundstaging, etc, combined with musicality, the XS is well worth the bump over the 5i. On the other hand, the 5i, would certainly be a better choice than many similarly priced options. I felt it was just as enjoyable as the XS, just not as detailed. I really could see some people choosing it over the others... They all three really get to the heart of the music.
I have been listening to the nait 5i and just switched over to the nait 5xs and found it easier to drive my b&w dm3000 that require min. 100 watts. It seemed to have a lot more then 10 watt differance between the two. Both have that great naim sound.If you dont need a lot of power get the nait 5i.