Anyone into cassettes?

Yup, cassettes rule. I have ditched my modded Oppo set up in favor of a very simple relatively unmodded, untweaked portable walkman type cassette player with vintage earphones. This very uncomplex system produces dynamic, uncompressed, open, clear and uber musical sound. No transformers to muddy up the signal, no fuses, no ground, no AC power, no wiring and cabling half of which would be installed backwards, no capacitors.

I still have my Nakamichi 581Z and numerous cassettes I made from my vinyl. I think they still sound great, and I agree: next best thing to vinyl!

I recently gave away about 3-400 cassettes that I'll never listen to and currently have over 400 cassettes of mostly recorded music and some pre-recorded music.

I had a Nak BX-125 for many years, sold it, and now have two 3 head cassette decks that I really like. A Harman Kardon TD392 and an Aiwa ADF-660 that were both very inexpensive.

And I agree with Ebuzz, cassettes are the next best thing to vinyl of which I have about 1200 LPs and only 2-250 CDs

If you are using old tapes i.e. 30-40 yrs old there are a number of things to watch out for.
Although the mag tape portion is absolutely fine and probably sounds as good as it did on day 1 (subjectively)sometimes the leader tape can lose it's stickiness (rather like dried out cellotape) and the danger here is that the sudden shock of hitting the end-stops, either by playing or winding, can cause it to become detached. I wouldn't have too much confidence in the splicing kits sold on e-Bay if the kit's leader tape is of similar age.
Gently hand winding and avoiding the machine's automatic stop sensor is recommended as a preventative.

Next up is the pressure pad at the tape head. As with the leader tape these can drop off altogether or lose their tension (you'll notice immediately because tape speed regulation will be all over the place)
Tape jamming is rare and can be a problem if it happens in the middle. Long time ago I used to have a manual winder for the awkward ones that motors simply couldn't drive beyond that point.
With less severe cases it could be solved by fast winding to the opposite end then rewinding completely to re-layer the tape. Sometimes the housings and mechanisms were too cheaply made.

FWIW I've found the most reliable mechanisms and construction are in the Deutsche Grammophon tapes. Next are Decca.
EMI & Philips were sent by the Devil. ;^)
Hope this helps.

Speaking of the pressure pads falling off there are some very informative YouTube videos that explain how to reattach the little feller or in case It went Missing in Action how to replicate the felt pad and attach it. I have reattached five of the felt pads in the last few months. It's a piece of cake.