I've heard the K1000's with the nOhr se9 several times, and must say that it is a bargain for that price. Each time was with stock tubes, and I thought it was an absolute necessity to use the Stefan Audio Arts Equinox cable with it to sound best. This, of course adds another $200 to the package, but it is still a bargain, IMO. I've never heard one with tubes rolled.
I've had the ASL OTL32 for a little while now. After rolling some tubes, I've settled on some RCA 12au7 cleartops for the moment. Without any extension cable (the OTL32 has a direct XLR connection), the sound is really nice. Occasionally a bit bright with some recordings, but I find that true with many phone+amp combos (including the nOhr), as I believe this to be the fault of the recording or source, more often. As far as power is concerned, I'd say that it is "ok" for the K1000's. Yes, I can drive it to clip, but only at volume levels just beyond my personal max anyway, so it is not too much of a prob. I know it is not the "best", or my last amp for the AKG's, as I've heard the K1000's from a pair of 140wpc CJ monoblocks, and nothing has come close since. There are times when the ASL does not give the feeling that there is a whole lotta headroom when driving the AKG's. But for the price I think the ASL is a good value. Is it better than the nOhr? I can't honestly say, as I've not compared them side by side, and my audio memory is not that good. Neither will be your last amp with the K1000's, IMO. With the Equinox cable factored in, I'd go out on a limb and say that they are comparable in price and sound quality. With their respective different preamp & output capabilities, those should be more of the factors in your decision, if necessary. Or if you can live without the Equinox, the nOhr is dirt cheap.
I've not had any QC problems with my OTL32. It is a beautiful looking, and solid unit. An interesting note (to me anyway), is that my two headphone jacks (XLR & 1/4") are reversed in location from the pic on Divergent's site - not sure why the diff. BTW, my Ety ER4S' sound great out of the OTL32, in both high or low-impedance mode. In high-mode, there is a bit of hum that is detectable, but that is from the high gain at this setting, I believe. At the low setting, there is less punch, but the amp is dead quiet. Also, having two headphones plugged in simultaneously lowers the power going to the AKG's XLR jack considerably, but has no appreciable effect on the 1/4" jack volume level. I haven't experimented with the OTL32 using low-impedance cans yet, but I can't wait for my A-T's to arrive for that. Hopefully soon.
Going up in the price ladder, I'd say that the RKV is a solid choice at just under $1000. You could probably be happy with that setup for a long time, if not forever (right joelongwood?).
There are many who can also atest to the Fishers with the K1000's. I haven't heard this combo myself.
As a Conrad-Johnson fan (see above comment) l'd love to hear the K1000's via the CAV50 (or 60, or 140!) integrated tube amps. But not until I can afford it.
Bottom line (again, for me anyway) is that the K1000's sound best with tubes to warm them up.