The default brushes are alot more harder to use than the filters. I dunno if you ever tried making anything with only the default brushes, but its pretty hard. Its easy to do things with the filters because there are tons of tutorials on them, and all you have to do is follow them, and most of them are only like 5 steps.
filters all the way thats how i used to do most of my work in 5.0 b4 i got cs2 ^_^ filters rock no doubt bout it
Just another trendwhore IMO. I used to use only filters when I started out and all I ever heard was "Use brushes" I do whatever I want whenever I feel like it. I have no particular style.
Definately has to be defaults. You can be more creative with defaults, thats my reason. Filters mostly do the same thing everytime, but with brushes you can change the options in the brushes window... yeah. cool beans.