I got the larger King model for making some knitted blanks for dyeing. It looks like it will get the job done. I've been able to produce both flat and in the round knitting without too much difficulty after a little practice. I find I need to pay attention, though, because it's hard to correct a mistake only a few stitches after it occurs.
Be aware that the King model knits at about 3 stitches to the inch. So far I've tried worsted and bulky weight yarns, with the worsted being quite a loose knit and the bulky more loose than if I'd hand-knit. I haven't yet tried a super bulky yarn, and I'm a bit concerned that it will be too thick for the needles to grab consistently.
In short, the Express King should work for my purposes, but it may have limited general utility.