as the title says, I'm a big boy. I currently ride a Giant Sedona hybrid XL frame. I really like my bike. I tend to ride 20-30 miles at a time, done some 40's. I test rode a tricross XXL and really liked it. Granted, it was out for about 15 minutes all street. I sprained my lower back a few years ago and occasionally reaggravate it, though never from riding. I'm very comfortable on my hybrid. (LBS told me my Giant was actually too small for me) I'm nervous about riding in an aggressive position for hours. (I rode an old schwinn in my teens, I'm mid 30's now.) Assuming this won't be an issue, I heard CX bikes are much better for the riding I do over the traditional hybrid. I don't curb hop, but do still go into grass, gravel ( I think that's what "fire" trails are?). And as I said, I'm quite a bit of weight, and terrified of road bikes and skinny tires. LBS said I'd get a much more efficient ride and would go much farther with a CX and actually ride more.
basically, should I be on a CX?