Where is it and why?

hangarbrno.cz - playground of Adam Ondra, 2 halls, boulder setting every week, every month 30 new boulder set into Challenge, good coffee, nice toalets, vibing through whole day, ...

That looks nice! Already thinking about visiting.
Is ondra training there, is it a comp style gym?

That'd be my home wall 😎

I guess it's comp style. I saw Adam there, once in 6 months. But I visit the gym 3 times a month.

Unpopular opinion: it depends.

I know many people that are absolutely obsessed with Moonboards and train pretty much exclusively on one.

Many people like gyms with set routes.

I like spray walls. I find Moonboard too repetitive and limited. Many set problems are of the "new style" type which has little to do with bouldering outside. I prefer to set my own problems and so a big, nice sprayway is my favorite.

And I do mostly specific training so a pullup bar and campus board is what I use the most anyway.

I think this is not really an unpopular opinion, I like to visit gyms with widely different styles. At the moment one that is focused on training for outdoor sport climbing and therefore more board-climbing style. The other one I frequently visit is more comp style.

Board climbing (including Spraywall) is a very good training for both and "setting" your own routes is good for creativity. Climbimg routes set by others is good for leaving your comfort zone and beta reading.