At one time or another I have mixed to almost all of those media. Not for clients, just doing my own stuff. My opinions -
1) If I want something quick and dirty (works in progress etc.) , I mix through the board to a cassette. Very portable, very cheap, reusable. A nice cassette deck with Dolby C sounds plenty good enough for this purpose.
2) Prior to starting to collect plug-in effects, I liked mixing to DAT (although I had to borrow one). Nice sound quality, good metering, easy to use.
3) Now I do almost all mixing (except situation #1) on the PC, then export to a 44.1/16 Wave, burn it to a CDR. NOT a CDRW. Portable, plays everywhere, and at less than $0.50 very disposable.
4) When my band gets together to have the classic drunken jam session in the studio where there is no intension of creating a finished product, a VCR works quite nicely. You can record good quality, run 2 hours or more without changeing tape, and its cheap. Plug it into the board and forget about it. Listen to results, laugh about it, then re-use later.
My 2 cents....