I was reared on cassette - all the albums I got from when I was 7 until I was, oooh, 20 or so, were tapes - but I have to say I'd sooner have LP or CD, and will generally only buy a tape if the release is not on CD or vinyl. However, I'd buy tape before CDr. Tape players can be picked up pretty cheap nowadays, and it's reckoned an old 'good' one is likely every bit as good as a brand new one, as the technology hasn't moved on since the heyday. That's what I'm told, anyway.
Yeah, sometimes an old-ish tape will play slow, or even chew, so it's a bit unpredictable. Mind you, the vast majority of the things I have from 30, 35 years ago play fine, so it probably is just a case of you being a little unlucky. Tapes, I think, are more durable and can take a bit more hardship than vinyl, but the big drawback is not being able to get to get to a particular point, or track, quickly. But, as you say, there's plenty of good stuff still being released on tape only, so from that point of view it's worth persevering. And my tractor has a tape player, so all is well!