Slice!! I've had mine since they first came out, and it is great! Somebody said that after awhile the cuts go wonky...that is just the charge winding down. I use mine plugged in. If that's not possible at a crop, I have always been able to find someplace to plug it in, then when I need a cut I bring it to the table. Then I plug it back in when I'm done.
If it's fully charge I don't have a problem with wonky kuts.
The Cricut Expression machine and the Sizzix Big Slot.
With the Expression you should also get Sure Cuts a Lot 2. With that program you can use just about any computer font out there. You can also turn jpg files into cutting files. Also there are TONS of SVG files out there that will allow to expand your creativity to a new galaxy!
The Sizzix Big Shot is universal system that cuts and embosses. As far as manual die cutting systems this is the only one you will need. All of the other dies from the other manual die cutting systems out there. You can use all of the dies and embossing aides from Quickutz, Cuddle Bug, Spellbinders as well as the Sizzix original dies.
From what I have read that Spellbinders work just like the Big Shot. I do not have the Spellbinders System, but the die plates come with instructions for the others as well.
I also vote for the Cricut Expression and Sure Cuts A Lot. Again - as someone said before me - I love the various cartridges for simplicity and the time element but when I feel more creative the Sure Cuts A Lot allows you to create anything you want.