Mark,
I have the Skil 77 Mag. I used this thing to cut EVERYTHING. I recently loaded it up with a diamond blade and chopped into my fireplace stone to inset an insert I was having clearance problems with (see post in OT about Fireplace Insert Issue...complete with pics!). She was 4 years old at the time but handled the job quite well..even tipped 90 degrees! I am a big believer in the capabilities of this saw.
I also use it to cut up plywood into more manageable pieces for the TS however I've added a hardboard shoe to improve smoothness and provide mark-free cutting on expensive plywood.
However, all that said, when I free up some funds in the future and if I feel the need, my next saw purchase will be the Festool Plunge saw.
Otherwise, the Skil 77 Mag is still going strong.