I'm not too terribly impressed with the yellow pumas, we've gotten a couple rounds of them in recent history. First tried em back before Christmas, taking one just didn't get me "there," so to speak (in contrast to the green pumas, which I LOVED; the greens had to have been MDA, I haven't seen pronounced psychadelic glistening from ecstasy tabs any other time). I countered my disappointment that night with a blue playboy 2 hours later, followed by some massive deemster dosing a half hour after that. Hell of a time.
I dropped another yellow puma a couple weeks ago at a show, that time about 45 minutes after yet another blue playboy. It was a great night overall, though the roll didn't feel much amplified from the times I've taken a playboy by itself (those things are fantastic). I'd say the yellow pumas are clean with a decent MDxx dose, but nothing special (still beats anything with meth, imo). I remember speculation on PR about them being MDEA, I'd wager that's a legitimate possibility.
I tried an Ecko about half a year ago, yellowish in color... couldn't tell for sure at the time since the lighting sucked. I'd gone a few months without rolling, and that night kicked some major ass off of just one pill. Felt a clean, moderately strong roll, very satisfying overall. If yours pack the same punch, count yourself down for a great time.