Jeff
For the first ever I'm going to disagree with you,
I think for the beginning woodworker, the guy who thinks cutting a straight line is a major accomplishment, cleats or braces is a good simple attractive method of building a rack, that can be torn down, and put back together. Granted my 3 way Questeds live on a pair of screwed side to top and bottom plate Birch racks that are 25+ years old. For the beginner I'll suggest cleats.
Love My Keg jig, my Biscuit jointer and like Denny the interlocking bit ( My favorite is a Box Joint, and I recently built a Client a pair of Box Joint/Cleat racks that he could ship flat and not glue!
look at it this way the $30 for the Jig will buy a Decent Blade for the beginners saw, or a better saw and drill!
The Idea of an extra 1/8 inch in each direction is a given to anybody who has rack a bunch of abused 80s gear, not everything is built to standard size and having a top and bottom space with some clearance for some bent chassis is a godsend! Also think rear rails! great for PSUs and cable ties! I wont rack without them!
Eric