I've used a Tascam 244 for years, a high-quality machine now available for about $300 I think.

Best quality 4-track cassette machines run at double-speed (3 3/4 ips) using a DBX noise reduction system, the 244 does both. (It's nice to have a machine that you can run at either speed, to get maximum usability out of it.) Avoid Dolby C, it's just plain ugly-sounding.

Also avoid track bouncing--if you limit yourself to 4 tracks only, use the best mikes you can get ahold of, and make a nice clean recording, you can then take your master tape to someone with a decent mixing board etc to do a stereo mix--you can add a bit of reverb and such at that point.

As to whether its worth making a CD, well do people want to hear your music? That matters a lot more than audiophile qualities. Bruce Springsteen's album Nebraska was mastered from a 4-track demo cassette he made at home, as a pre-production rough take to teach the songs to his band. He carried it around in his shirt pocket for a couple of weeks before he decided that the minimalist production was just right for the songs and album concept, and they didn't need the full band treatment.

I bet he used good mikes though.

Willie-O