RE: Trajectory
The range of the crossbow is the same of the compoound vertical bows. Most people (with deer) limit their shots to 30-35 yards. It is not that you are not accurate out past that distance, but the time it takes for the arrow to travel out that far. In the time it takes the arrow to travel to 45-50 yards, a deer can move to make any accurate shot a bad hit (just because the animal moved).
Me personally I do not like the compound crossbows becasue of the extra maintaince and dependicy on the proshops for repairs. If you look in past threads (just recently) you can see some pros and cons on both the recurves and compounds to see why I prefur the simplistic nature of the recurves
Good luck and welcome to the world of crossbows. Ask any uestion that you need to.