I wouldn't worry about the service side of tube amps personally, tubes take a lot of hrs playing them at crancked volumes to wear out, I change the tubes on my main gigging amp every two years just as good practice and that amp gets a lot of play time at loud volumes so using a tube amp at home with lower volumes when you are not pushing the tubes hard at all they will last a long time, plus it's only the phase invertor and power tubes that do most of the hard work so you don't need to change all of the tubes. The electrolytic capacitors will need replacing every 6-10 years but that's not too expensive to have done if you don't have the correct knowledge on how to do it yourself.

I do all my own amp servicing and most of the repairs plus I do the same for several of my friends amps and have built a few from scratch, from my experience newer amp are no where near as well built as the stuff from the 60's to early 80's but everything seems to be built cheap these days.

But if you really want that tube tone you need a tube amp. Do your research well before buying and decide what features you want and need, different tubes do make a small difference in tone and sit in different frequency ranges, for example the 6L6 has tighter bass and treble response whilst an EL34 has a looser bass response but more mid and allows the mids to cut through a bit more but transformers make a bigger difference especially the output transformer so take that into consideration when doing your research.