A bit of a tangent maybe, hardly a hi-jack. I spent a bit of time with the current Naim 202/200 separates over several sessions at a dealer, and owned the Nait 5i for close to 2 years. The Naim separates are very fine, but very Naim; all of the Naim virtues of rhythmic drive, nice tonal balance, great mid-range, bass that has heft but good manners too. The separates are of a higher calibre overall than the integrateds under discussion here, as they should be for the price. Still, they have the Naim voice which you may or may not prefer; not the last word in soundstage, a sense of air and bloom, delicacy of decay of notes etc.
I think the little Nait 5i holds its own against the Krell 400 xi or the Simaudio 1-5, as long as it is used in a suitable application and set-up. Naim is pretty particular about partnering, from speaker cable and interconnect to equipment rack and speakers.
I might add that I may not have heard the Krell at its best; some devotees of Totem speakers, which I like too, say Krell is a great match with the somewhat forward or lively presentation of the Totems.