The comfort difference is HUGE!!! I used to ride a pair of $100 Fox Trackers. I have since upgraded to a pair of Alpine Star Tech 6's (got a good deal on a new pair for $180). It's a whole new world stepping into these boots. I believe they have actually made me faster because I have fewer problems shifting and controlling the rear brake.
If I am riding trails in a less agressive manner, then I use Garne Trials boots, they are more flexible and eaiser to walk in. If I'm dirt tracking with a lot of jumps, then I use my stiffer boots alpine stars or arc pivot ankles.