well, your
gw brushes will still work fine...they won't burst into flames if touched to a warmachine mini

...
the new p3 brushes are a bit over-priced...
windsor & newton are the hot trend...
da vinci and raphael are a close second...
i use
gw brushes for my metals, and W&N series 7 for my colours...
my
lgs does
gw for 20% off, so the
gw brushes are a good deal, but they have to be replaced every 6 months or so...
W&N are dicounted deep on dickblick.com...i'm told these will last about a year of heavy use if well taken care of...we'll see...
i paint everyday, so my brushes get a lot of use, and fine tips start to fray eventually...my fine brushes are always the first to go, and the large brushes last a lot longer...
hope this ramble helps a bit...
cheers
jah