I've simply put more hours into this game than in the (Dark, Demons') Souls games combined.
I'm not a big fan of deterministic rogue-likes, where often it's just a matter of data collection and action execution in the correct sequence or sequences. FTL is no rogue-like under this aspect.
It surely can be harsh without your playing exceptionally bad just because of the random factor. But the same factor brings you out of your comfort zone and sees you trying out new crazy stuff. if you're up for the challenge, that is.
It has cheese tactics here and there, weak AI (perhaps its biggest flaw yet) and some special event chains are harder to complete than "French-kissing a cobra" and surviving. But, but, but... it's delightful! Wonderfully simple yet attractive graphics (even better in Advanced Edition), hypnotizing soundtrack, manic ship to ship action, especially interesting with all the variety brought by AE and good pacing, thanks to the fleet pursuing you.
The game just works brilliantly. I didn't have any specific expectation when I first got around to playing it. Some hundreds of hours later, I can definitely say this one will stand the test of time.
Once you FTL, you can't stop!