@badong, Im pretty sure I understand the arguments for and against using radiant to model with, but personally I am more comfortable using it to make geometry and texturing directly onto the surfaces, then any other modeling program and texturing system, Ive worked with or tried out in the past.
we don`t need max or maya etc if we find radiant good enough, and not everyone here can afford those modeling programs, although the spline based one I used for several years was over £1000 and that was about 10 years ago.
I dont think its made any longer but if it was, it would probably be in the same price bracket as max… anyway, if I had the money now, which I dont, Id still likely pick radiant… imo, the 3d cam window alone makes up for a lot of it`s short comings.
and being able to make a model 2, 4 or even 8 times it`s final size, then scaling it down for in game, over comes the limitations of the 1 grid unit for editing brushes and aligning textures.
of course money aside, its personal choice, some people probably hate radaints interface, I guess Im just lucky I found a free program which I love working with 