For myself, hardware acceleration in FF has been a huge boon - especially for my AMD fusion netbook (has a decent GPU) - made FF about as fast as Opera before Opera got HW acceleration. Through this and newer graphics drivers, my PCs have become much faster now than they were new I waited awhile before updating to FF4 and let everyone else deal with the initial problems. Despite that, I do remember having some kind of font problem related to the hardware acceleration, but it was quickly fixed. Otherwise no issues on many machines (including 6 year old laptops). Saying that, for people who do have issues with hardware acceleration - it can be a big obstacle and a huge pain. Edit: Agreed on HTML5 though - Adobe Flash is significantly faster on the netbook. I can't play HTML5 with 720p fullscreen without it being jerky and unwatchable.