Yes, that is true. My main complaint with AVAST is that it slows down file deletion, sometimes to a ridiculous extent. And it's a bit more paranoid than MSE, requiring some exceptions to be created (although nowhere near as bad as Symantec!)
That said, even MSE was getting to be a pain toward the end. I had to exclude browser files from it, and rely instead on MBAE, in order to get adequate performance. Ironically I haven't had to do that with AVAST yet. (Also still running MBAE, although I probably don't need to any more....)