yes the Aerons have a reputation for unreliability as well. and it was the tau 7 I was complaining about. I have shot them and the person who owned it could not get it to work correctly on multiple occasions over a period of time and made quite a disturbance in the range while he was doing it. The tau 8 looks quite crude compared to better made PCPs but I have not heard bad things about them.
Older match pistols can be resealed and are not inherently unreliable. Unless you want to shoot at competitions I would not worry about out of date cylinders as they have never failed in normal use and by law do not require testing as they are too small. (I am aware that a pcp cylinder failed but it had been abused)
I sort of collect walther target pistols