I've never been to Springs but Ponds Forge and EIS are both very busy but for the price of membership its understandable. Both places are much quieter in the mornings. I normally go before work and never struggle to get on any cardio equipment, however I always find the free weights area packed no matter what time I go.
I find the lack of space a problem, they have really good equipment but not much matting/ free space to be doing kettlebells, weights, stretches etc. however, if you are after cardio equipment then I think it's worth the membership.