First of all can I pass on my thanks to Oxford audio and Fanthorpes who were both great in their own way. I cannot say how good Alastair in Oxford audio was in helping me choose an amp. Fanthorpes were brilliant letting me home demo and also putting a deal together. These are my rather limited opinion of the amps I demoed and my final decision was based upon synergy with my speakers and future. Please do not take offence at my ham fisted descriptions.
Devialet D200/400 - before i started this, the d200 was the amp I expected to end up with. I could reduce box count and it looked fantastic whilst delivering functionality. I heard this on my own speakers and a pair of very expensive Magicos. However I found I was luke warm with this amp. It didn't do anything badly but it also didn't do anything particularly well and in some regards isnt really a step up from the Sn2. If sounded muddled and unengaging to my ears. Things only really got better at d400 level however at £10k just wasn't worth it.
Audio research I heard on Wilson's and magico. They sounded beautiful on the Wilson's but lacked the drive for the magico.
MF M8 - At first I wasn't kean but I think that was more to do with it being a new amp. I really liked this amp. Good looking. Sounded fantastic in some regards. Sweet top end and very powerful bass. Touch warmer than naim. If I was being picky I would say the soundstage is a little restricted and in your face and a little bass heavy but that may be my environment. I could happily live with these.
MF nuvista 800 - Much of the MF sound of the m8 but to my ears more balanced and with better sound stage. Just amazing. Weighs about 70lbs though lol. This was both my wife and my choice having heard it 3 different times.
Naim sn2 - I love naim. Have had it for a number of years. However I struggle to see myself going back. The amp sounds thin, veiled, shouty and almost lacking bass when compared to the above. I know there is a price difference and probably some bias but we were both a little sad that we felt that way as we love the brand. Maybe with better matching speakers that may change.
For sale on an auction site naim sn2 plus hicap Dr sounds beautiful