I use different styles depending on what I'm working on - I do like the pointed sash style brushes for a broader, soft blend (Ken Oliver, Clarity Stamps, Tonic and Scrapbook.com have branded sets or you can find them individually on art sites or Amazon).
Great price on the Tonic ones at SSS
HERE.
I have some of the cheap toothbrush style ones but have found that not all brands are equal - some are soft and some are very stiff. On Amazon, the Beautia brand has been my favorite.