I don't get worked up about tubes wearing out, many of my tube amps from the 60's and 70's still have original tubes. I don't listen to my system more than a couple hours a day, so I haven't seen the tube consumption issue many reference. I don't know much about the brands you mentioned, but I would look toward older proven designs. There are some really great tube amps from the 50's, 60's and 70's, that with the right updates can be very reliable. Long term serviceability is the key to maintained value. Original McIntosh, Manley, Scott, Eico, Pilot, Fisher, Quicksilver, Manley, and a bunch of others hold their value really well. They are also serviceable long term, and are made with quality components. My 3 things would be:
Match the amp to the speaker - the Zu's will open the door to lower watt options that can sound very nice, but might limit your speaker options down the road.
Serviceability- look towards amps / manufacturers that have been in business a long time
Power tubes used- my preference for power tubes are E84 and 6L6. I like the sound of these tubes, and they offer me the power needed to run my not as efficient speakers.