I typed this up earlier today, then waited, since we weren't sure about what you were asking.....
Personally, I don't like either one of them. There are cleaner ways to cut picture frame miters. I use a shear-type Lion miter trimmer for picture frames and molding. Unfortunately, Lion has gone out of business within the past year or so. Grizzly or some other Chicom has cloned it. Power miter box also works better and faster too. But, if you're one of those guys who exclusively uses hand wooddorking tools instead of the tailed type, then the power miter box would be a no-no.
The #100 can be used as a corner clamp if you take the saw out, but the saw guide gets in the way during setup and assembly (as Outlawmws said). I got rid of mine 35 years ago when I got the Lion trimmer to replace it and have never regretted it.
The bench-mounted #400 clamp can be handy, but you can only do one corner at a time and it can be awkward to use for large frames. Mine just sits on the shelf most of the time. Individual corner clamps work better and faster IMO.
