To try and offer some perspective, I've heard it said that Triumph is the most reliable of the European bike makers, and from what I've seen there aren't any major or frequent issues with the R3 generally speaking.
With all that said though, a rocket really isn't about reliability or value for money. It's a genuinely unique bike that is all sorts of fun. I used to be strictly Japanese for everything, being completely unwilling to compromise reliability for anything else, then I impulse purchased a rocket (the old model). It has given me a couple of small issue but it is an older bike now, but it is completely worth it honestly. But everyone has to draw that line where suits them, my advice is go test ride one, you will work out instantly if it's for you or not.