Unison Research

No experience with the three you mentioned, however, I was the proud owner of the Unico SE tube integrated non modified. http://6moons.com/audioreviews/unison3/se.html

I was was very happy with the deep holographic soundstage, separation of instruments and mildly warm presentation via Mullard  6922’s. At the time I was driving Dynaudio Contour 1.4’s and a ClearAudio Performance SE turntable. I believe they are a very good value and quite attractively built with high quality internals and power supply. 
Best of luck in your search! 

Happy Listening,🎼
Tom

I don't own, but a friend of mine has the Triode 25, and he loves it. He has them mated to some Harbeth speakers.  I've  heard his system numerous times, and it sounds really, really nice.  He does use both the triode/pentode modes.  Really nice looking too, if looks are important.
John