I've tested my 3C 2S rated lipos using a data recorder and they are closer to 30C than 35C. The name brands may be better as far as delivering the rating, but some of the cheap lipos are not bad.

There's also a world of diff in an overrated 35 or 40C versus an overrated 25C. The higher rated ones can lose some of their rating and still have plenty left, but the overrated 25C doesn't have that much cushion. If it goes under 20C, you'd have a lipo that was getting way too hot in a lot of setups cause it couldn't supply the current.

I don't buy anything less than 30 - 35C anymore.