I have or have had several.
WATP Express are probably one of my favs, but I like the 4 mile & 3 mile best. 1 & 2 aren't a challenge even on days I need something quick. 1, 2 & 3 mile use the stretchie band - I like it, but every one I've had breaks after a short time.
I have the Christian version 1 & 2 mile - again 2 mile is better. I like the music.
Walk & Kick & Walk Strong are both 30 min - about 2 mi I think, and have a bit of interval training. Walk kick has some basic kick boxing segments - easy. Walk Strong uses the 'stretchie band' for some upper body stuff in intervals.
WATP ABS I like - it uses a belt with stretchie things attached. The 3 mile is a good workout for me for 45 min.
I just bought WalkAerobics Weight Loss walk - I thought it was too easy for a 4 mile walk for me. Not bad, just not as challenging as the Express 4 mile. Although this was released in 2002, it is probably early 80s. Kind of corny - ie. she's in her 'living room' w/ a fake 'window' behind her - suddenly the scene in the window changes and she talks about it storming, etc. They are wearing leotards & leg warmers.
Also just got the WalkAerobics Fat Burning - did it this morning and it was tough. Did the normal walk moves, some jogging and did 4 mi in 45 min. Then had 15 min of floor work that was a definite challenge. This was released on DVD in 04, but also probably late 80s - has some of the people from the Express DVDs on it and they're noticably younger - again all are wearing neon leotards. I really like this one, tho.
I bought the WalkBlaster system, but haven't opened it yet as it's a 'prize' for me.
HTH