Frankly I have all the not electronic ones except the wizard. The newest one is my favorite by far. It's called the Boss Kut. With my bad hands, I could no longer use the QuicKuts, I'm not a big fan of having to roll acrylic mats under rollers like I have to do in my sidekick and even my Zipe Mate and even the ball on my sizzix hurts when I have to do a few cuts in a row. The other night, I had to make 18 2006 and used my new Boss Kut and it was just great! No sore hands/wrists afterwards! It has a mat for the sizzlets too. There are a few sizzix dies that I'll have to compare to some QuicKutz ones like the tabs which I really like, but if the QK dies work as well, the sizzix will be put up for sale with its lollipop alphabet , frog, pumpkin, frames, dinosaurs etc. I also have a little ZAZ that I've never used and that I'm planning on giving as a gift to someone. The Boss Kut alphabets are really nice too and they come pre-foamed. I'm part of a QuicKuts club here and heard yesterday that the QK dies will also come pre-mounted in the future. One of the other reasons that I fell in love with the Boss Kut was that I was able to use the smallest size of scrap paper, as I can turn my die in any direction I want. Yes it is heavy, probably as heavy as the sizzix, but I am now thinking that's a plus as I really get frustrated with machines that won't stay in place.
Thankfully I just became a retailer for the Boss Kut so I was able to get a good price for mine and for the alphabets.
So here is what I think, first figure out what dies you like the best. For me, since I'm in a downsizing mood, the regular sizzix dies take up more room than I'd like, so I'm going to concentrate on smaller dies like QK, Accucuts and Boss Kuts. I'll be posting an ad to sell off my other stuff separately!