In reply to DeanD:
The two dedicated bouldering walls both have a lot to recommend them and not wanting to sound like a fence sitter but I'd probably say try both:
I've spent a lot of time at TCA but only had one visit to Bloc (lack of time not lack of inclination)!
The problems seem to be a bit different in style between the two walls, TCA seems to me to be a bit more biased towards powerful moves than Bloc which had some cracking balancy stuff last time I was there. Bloc feels a lot more highball than TCA, the extra height and the odd rather tenuous high crux move makes a lot of the problems seem a lot bigger!
It is probably a personal issue rather than the wall but I found it harder to warm up at Bloc, probably a style/lack of talent thing.
If you have time then definitely do both, if you are stuck to just visiting one then I'd say it comes down to personal preference:
Like slabs and technical stuff: Bloc
Want a really good upper body workout: TCA
Scared of heights: TCA