What do you see as the downside of tubes?

Finding quiet, high quality, good sounding unused tubes.

I've owned some very good and quite expensive SS gear over the years but none of it has ever sounded(to my ears) as believable or satisfying as even modestly priced tube gear.

Many years ago, after hearing so many good things about tubes, I decided to replace my SS Symphonic Line RG-4 monos($9800pr) with a pair of 60wpc QuickSilver's(maybe $1500 pr). Long story short, no contest. The QuickSilvers just plain sounded more believable; more flesh on the bones, more relaxing and just plain more enjoyable. I found myself listening more often and for longer periods without the usual boredom setting in. The only downside to the QuickSilvers was their rather wimpy bass but I really didn't mind since everything else was so good.

After three years with the QuickSilvers I moved on to CJ monos(2 years), VTL monos(7 years) and five different CAT preamps over at least 15 years. Other than a power tube in one of the CJ's causing me some minor grief and an occasional re-tube, all of my tube gear has been trouble free

Over the years I've auditioned various SS amps and preamps and as good as they've been tonally, they always come across sounding 2-dimensional and rather uninvolving(to me).

Currently I'm suffering(NOT) with an Atma-Sphere MP-1 Mk3(w/phono) and MA-1 Mk 3 monos. Let's see, that's 56 tubes not including the four in my tubed CD player. For almost two years my A-S gear has been totally trouble free and the Telefunken ECC88's in my CD player are still kicking after being used in those 5 CATs over the 15 years. Not bad!

The downside to tube gear, it can be addicting. You probably won't want to go back to SS. Yah, you may have to bias your integrated on rare occasions and depending on how hard the tubes are driven you may need to replace a few of them over time.

Unless you're completely neurotic I doubt you'll be worrying about the status of your tubes while you're enjoying the music. That has got to be one of the lamest reasons for not going with tubes I've read!

Heat may or may not be an issue depending on your room but even with my 28 power tubes running Class A, it's not for me.

As EveAnna Manley would say, "Tubes Rule".

If a tube amp (or a class A solid state amp, for that matter) is located in close proximity to a room/house thermostat, it can create havoc with maintaining a constant room or house temperature.

The real down side is that you may be perceived as a picky person and ordinary things are not good enough for you. You pursuit your ideal to the extreme and don't make compromises for the 2nd best. You are too confident in what you believe. Anyway, you are just above this world...... ;-)