I know a few people who learned there at one point or another.
It’s a ba’al teshuva yeshiva which fluctuates in numbers; usually rather small (last I spoke to anyone there, there were something like 11 guys). As far as I recall it’s located in Kollel Chazon Ish in B’nei Brak. The concept as I’ve seen it is more or less to bring you into a Charedi environment and to help you head in that direction.
The shiurim are to prepare you for “regular yeshiva-ish learning” along the way and the rosh yeshiva’s shiur is on par with your average normal yeshiva shiur.
It’s not for everyone, but no yeshiva is. That said, you may very well find you like it.
…That’s about as much as I can cover without really knowing what your questions are.