They're not popular, but they're good. Out of maybe 200 games in ELO last week, I saw Rescue about 8 times. I lost 7 and drew with one. Some top players are using Rescue, and I believe the deck is:
Cliff, Sledg, Buckler, Anita, Daussone/Slyde/Tina/Wesley, Sue, Steve, Krash (Yes no Kerry, honestly she sucks)
No! Don't listen to Battery! Rescue are completely unplayable!!
...Actually he's right but I would much rather never see them again. But if you MUST, my personal recommendation would be to run Cliff over Sledg. Unless you're playing Pussycats, you just can't DR Cliff in Revenge... At 6 + 12, he is about as good as an 8 power if his bonus isn't blocked... And he can KO with a lot of pesky cards that might get through even if you old them. Cliff was what made Rescue fearsome, and somehow when Sledg came back, everyone forgot how good he was.
Running both is also legit tho, seeing Rescue has many usable 2*
Any Rescue 4*
Somewhat borderline legit I guess.
I personally like Nancy. After winning a round, put Nancy out. Still pretty scary. decent bluff, very scary if goes through