Hello, Jason @ Revive here, Just adding to this thread since we came up.
As to the comments on the KT, We feel they are basically pretty on par with each other but with different color. The Warm uses the Cinemags which have a nice low mid bump and pretty much are responsible for the WARM in most Warm audio gear. The KT's are a bit cleaner and sound flatter.
The Warm uses a linear PSU (old school power supply) which tend to send a bit dirtier but more dynamic in use with circuits.
The KT has aa Auto- switching PSU which is clean and fairly flat in how it responds to amperage demands from the circuit and so sounds as such.
As to the SMD question someone "quoted us" as saying. Our years of experience repairing SMD work (20 years on my side) as well as modifying units is that SMD does not last as long and once it comes up for repair, well often is toast.
This is an official quote from me Owner of Revive Audio.
We make recommendations on both audio quality and reliability for our customers sake and simply want to inform not push one over the other, after all its seems like so many people have their favorites so its somewhat subjective (source, music style etc).
We comment on quality of build and sound and simply try to steer people to the best outcome for their app.
What we have seen:SMD components do not hold up to temp, voltage spikes duration of use etc and when in need of repair, can often be un-repairable where thru hole can easily be serviced.
There are a number of reasons for it, but those of us techs know them.
As to sound quality differences there are subtle ones as well but mostly it comes down to quality of components.
SMD is also prone to lots more cold solder joints.
Our M76 is all Mil Spec, built to last and we haven't heard anything that can touch it save a vintage Revision with a full re-cap, but heh all we do is sell snake oil

See our feedback, I think it speaks for itself, but if not ask a friend not a random stranger

As always, send us an email or give us a call. We are always open to help people get what they need even if we dont have it and have to send them somewhere else.
I realize there are a lot of folks who dont trust modifiers but every NEW design is a modification of a previous OLD one so.....for what its worth.