REL reliability has been top notch.
My S1 is now 15 years old and has never had any issues. The gain pot is now slightly scratchy but that's probably through lack of movement. I have a spare waiting anyway should I need it. The power switch neon has faded a bit, I have a spare for that too. The sub looks and sounds like new after all this time.
I still have it because it is a good sub and I was very happy with it but my system and tastes sort of out grew it. Lack of low level input was the main frustration, there was no DD5.1 when it was built, plus I wanted something that didn't strain with the likes of Pulse et al.
I am not going to let it go for penny's just because of its age. One day I will find a good home for it, probably one with music more in mind than sub 20hz LFE