If I was going to get an SP cab, it would be the SP212. I tested it at Orange down south, and it was loud, VERY light, VERY small, and quite 'middy'. There wasnt a lot of bottom end, but thats to be expected.
The RS210, to my ears, is a very very good 2x10! I bought two after hearing praise on talkbass, then hearing them in person stacked at the Bass Merchant.
I sold a Berg cab....yes, a Berg cab, to get them. I didnt want another squat 4x10, although I would have liked to have kept the Berg, but nevermind!
Im quite picky with cabinets. I like warm punchy mids, plenty of bass, but not a shrill high end....cant stand plasticky tweeter sounds, (and thats a little like what the Berg did with the tweeter IMO.
Id sum up the RS210 as:
Small, easy to move, well made, handles volume, slightly delicate finish (needs the £18 cover), punchy, smooth high end due to the tweeter, plenty of lows, low mid kick. They are probably inbetween vintage and modern in terms of tone.