My 9zero7 is aluminum the carbon was out of my price range. My buddies Borealis is carbon I don't think borealis has come out with a bike that wasn't carbon. Borealis is one of the few carbon bikes that has rack mounts, most other companies think that the integrity of the frame is weakened too much. Fatback's corvus has them if I remember correctly. I have carbon bars and seatpost, that's where it will probably end for me, my bike already costs mote than my daily driver. I can't recommend carbon bars and foam grips enough especially if temps drop.
That would be one of my fears with carbon, no experience of it, just a fear; cracking around the rack mounts.
I'll probably sick with the aluminum since the weight, integrity, and prices are hard to beat.
I went down to my LBS the other day and picked up a used trek 3700, front suspension, hard tail, rack mounts, aluminum, etc. knabbed it for a solid $165. I was stoked. Owner of the Bike shop put on a new wheel, some sweet all terrain tires for mobbing around dirt and town asphalt which is what I was looking for.
I read about guys picking up bikes like these, putting wider wheels and tires, racks, what have you. Making a pretty affordable good build pseudo fatty.