Compiling BSP Levels is fast,-only full vis takes too long,which you dont have to necessary use.
a 10000 portal -which is low- takes only two minutes-the most to compile.
I am a fun of bsp,and till now that is what rf does best.
I make everything from bsp because i like the lightmaps,it is stable and fast,
and the bsp polys can block visibility,and have some nice basic physics effects.
What takes a little more to compile (two minutes more,the most) is faces that have small lighhtmaps like 0.15 which is very rare.
I like the inssurance feeling bsp gives,and the shadows can be a work of art to the eye if you experiment enough with the lights.
I make mostly dungeons with bsp and add staticmeshes for the round pillars and the occasional building's domes,rock cliffs and surrounding cave walls-Which is the parts of the levels that no one will collise with all the time.