I recognize I'm late to the party, but I have lots of experience with SWR gear so I'll air my views.
I don't think the Workingman's combos are good values. The WM 15 sounds okay in a store, but I've never been impressed with them at gigs. I think the WM 12 is blown away by others in that price range, like the Roland Cube 100.
When I tested Workingman's heads a few years ago, I liked the warm tone, but hated the anemic output for the power ratings. I bought G-K. I've recently been using some of the heads at a rehearsal studio, and I still like the tone, but the muscle just isn't there.
I've had a Goliath III cabinet for almost three years. Other than the 89 lb. weight, I think it's great, and a very good match for my G-K heads. When I bought it, I didn't know much about the vintage/modern tone divide; I just bought what I could afford at Sam Ash

confused: see how little I knew

?), and thought the G3 had the most clarity by far. Were I to start over, I'd probably go with a 2x12, but the G3 has never let me down. I wish it had a fatter yet more solid low end, but the tight sound always works, and it does reveal the distinctive characteristics of my instruments. Rolling off the tweeter gets it much closer to vintageville, so I keep it almost all the way off these days.
I've also used a Bigfoot 2x12, which I think is an awesome rock cab. It has serious bark and punch, and got me thinking about twelves. If you're thinking about a 2x12 and see one used for a good price, snatch it up.