Tube novice here. KT88 or EL34?

Hello everyone
I want to setup a second system consisting of tubes. I love my McIntosh SS but for some music I realize tubes are better. I auditioned the Cary SLi80, the Rogue 66/88, EAR 847, and the Unison Research Simply 2. Of the three, I liked the Unison the best. It was very musical, almost ethereal in presentation and I loved it and want one badly. It was auditioned on very strange speakers called Royd Ministrels which looked ridiculously puny but sounded remarkable. I want to stick with an integrated so it is all-tube sound and no mismatches (most separates are out of my budget).

Anyway, there are two versions of this integrated, one with KT88s and one with EL34s (I auditioned the latter). What is the big difference? The KT88 one is more expensive so I am wondering. I favor soundstage and musicality over anything else. I have a Sony ES CDP, and Paradigm Reference 100.2s with MIT cables (will these speakers do well with 12W? The Royds were a lot less sensitive and sounded fantastic so I assuming it will do fine). Thanks for any info, ideas, suggestions, as I am new to tubes. Arthur