Before getting too caught up in brand names, I'll point out that the Ridgid 3650 is a descendant of the Emerson made Craftsman contractor saws made prior to 1997, which became the TTI/Ryobi made Craftsman contractor saws until 2003. Also in 1997, the former Emerson made Craftsman contractor saw became the Ridgid TS2412, then the TS2424, then the TS3612, successively. In 2003 Emerson contracted with TTI/Ryobi to make the Ridgid TS3650, which later became the TS3660. All very similar saws with many interchangeable parts. AFAIK
, the new R4512 is made by Dayton, who also makes what appears to be the identical Craftsman 21833.
As far as Craftsman portables go that can be purchased with Sears cards, TTI/Ryobi makes the Craftsman 21828, which looks to be identical to the Ridgid R4516. I can't vouch for either saw...I'm just saying don't overlook something because of the nameplate. because things change rapidly and without doing some research, ya just never know who's making it or at what quality level...buy the saw, not the logo.
You might also consider the Cman 21829, which is a revision of the popular Ryobi BT3100. Not everyone's cup of tea, but there's an army of people making good furniture with them.
With that said, I think you'd be getting a better saw if you went with something full size (27" deep), cast iron or granite, with a belt drive induction motor. The hybrids, and new "contractor saw hybrids" have the inside the enclosure which saves some space. Put them on a mobile base, and move it around your garage or driveway.