I've just been playing around with them on small pieces (23mm x 23mm) and got so impressed I wanted to but 2 more just for convenience and not for need... Mine arrive a week ago and when I tried to reorder 2 more they don't seem to ship to Aussieland anymore.
I wouldn't necessarily recommend them for large items, however, small pieces, convenience and integration into MFT style benches, I'd score then 10 out of 5... the 4* was primarily based on the cost and not being everyone's cuppa T.
About to post a "project" on them and a link to a few hack videos I made.
If your first cut is too short... Take the second cut from the longer end... LBD