^^^ Ick + daisy chaining 2 = double ick.
I would NEVER use a Radio Shack branded product. Not to be a snob about it, but their stuff is pretty much the cheapest of the cheap Chinese crap (no offense intended).
With switch boxes, like MANY other products, you get what you pay for. Now, that's not to say that you should spend hundreds of dollars on one, but I wouldn't skimp on this sort of thing unless you absolutely don't care about picture quality.
As far as HDMI switch boxes go, if they work, they work, it they don't, they don't. Signal degradation is almost a non-issue. If you do run into degradation it'll be incredibly obvious (image dropout, "sparkles" in the image, that crummy super-compressed MPEG look, etc), so there's really no guessing as to whether your cables/switches are working to their potential or not. HDMI is the only A/V format that I buy cheap-ass cables for and have had zero issues with, ever.