I've got a Baader 8-24mm zoom and I love it (as I've mentioned in a couple of post here). I've had it for a couple of months now and I don't use any other eye pieces. It has a number of click-stops as you zoom in or out but you can stop zooming anywhere you want in between the click-stops.
It's supposed to be parfocal but the 8mm and 24mm settings are nowhere near the middle three settings. Doesn't take much to re-focus though and it's a lot easier than changing ep's all the time. In fact I'm getting pretty good at focussing as I zoom in or out.
It's my first expensive (for me anyway) eye piece but I couldn't be happier with it. (p.s. I bought mine from the US and saved $100)
