Picking a Tube integrated amp

Not sure what the buzz is surrounding the KT 150. The question I would ask is how do they sound? Not how much power they put out.

What don't you like about your McIntosh? Why do you want to move to tubes?  The Vivid 1.5's have been characterized as clean-sounding speakers delivering masses of detail.  If you are looking to inject a little warmth by introducing tubes then the Octave may not be what you are looking for, as it has often been characterized as having a more up-front sound that is vivid.  Could be a little bright depending on your room and phono cartridge. In any case, would help to know what you are looking for when switching to a tube amp.

Another vote for the PrimaLuna Dialogue HP Integrated, I have back to backed the PL against various amps, Plinius Haetonga, Music Fidelity M6i, Vincent SP-994 with Sa-94 pre and various Yamaha amps all in my system and the PL just makes the rest sound very ordinary.
I have various sets of el34’s and the standard KT88’s but it’s the KT150’s that really make this amp sound at its best for my ears. Once you settle on what main tubes you like then you can fine tune the sound in with a couple of NOS 12au7’s, my favourite pair of 12au7’s fitted with the KT150’s at present are the LA RADIOTECHNIQUE RT 6189/12AU7WA, I also have about ten other sets of NOS 12au7's and they all make the PL sound quite different. Bang for your dollar it’s hard to go past the PrimaLuna HP Integrated in my humble opinion and the fact they are so tuneable for a relatively small amount of money is such a bonus.
I have also auditioned quiet a number of other much more expensive amps with the same Vienna Acoustic speakers that I own in various Hifi outlets in the last year and I keep coming back to the PL as it is the most pleasing amp to listen to that I have heard so far. ... Cheers Terry

I'll toss in another vote for PrimaLuna.  I have the Dialogue HP.  A very solid and well engineered amp.  I have all the stock tubes and am very happy with the sound.  Really like the ability to switch from triode to ultralinear.  UL sounds more spacious,  dynamic, and extended on both ends. To me this is clearly the default mode (don't know what the Stereophile reviewer was thinking when he suggested the opposite--and then suggests his $$ separates has a touch more clarity.  Brother.  Just push the button man!) But sometimes like now, I enjoy triode when playing music in the background while I work.  The point is this is a very versatile amp.  The tube rolling options are crazy.  The one disadvantage of the HP is it's $$$ to roll in 8 power tubes!!  So if you don't need the power I would probably get the Dialogue Premium. 

I bought a Line Magnetic 216 integrated amp from a dealer. It blew a transformer and the company DID NOT give me any problem. It was shipped to a repair center and they replaced the transformer. I really like the LM Audio amp and it beat out a Primaluna, Rogue and Cary I had considered buying. My two top choices would be Audio Research and Line Magnetic SET amps.
BTW my amp might have had a problem with the heavy load I placed upon it by driving planar speakers. I think the more current a speaker demands should dictate how much current your potential amp can provide.