IMO the crossbow and the compound bow are pretty equal weapons when it comes to killing deer. I hunted with a vertical bow for many years before going to a crossbow due to a back injury. I am probably one of the few that would go back to hunting with a vertical bow if I could. No offense to anyone here. I am glad that I am still able to hunt the archery season as it is my favorite. Though the crossbow and the compound bow are pretty equal weapons when it comes to driving an arrow thru a deer there are somedifferences.
Compound bows requires more practice to be effective. I used to practice at least three times a week thru the summer and into the season, and I really enjoyed the time at the archery range. The xbow doesn't require as much practice to become effective. Not that I can't go to the range but I tend to go less.
Compound bows are a little lighter than an xbow and compound bows are easier to get thru the woods than an xbow.
I also hunt on the ground and I would have to say that an xbow is easier to shoot on the ground from a sitting position than a compound bow. Not that you can't do that with a compound bow. The shorter ATA measurements that are available today make it easier to do. It just takes some practice.
These are just my personal observations and as they say, your mileage may vary.

I love hunting with my Excal and I am counting the days till the season opens on September 15th. I will also add that David at Wyvern Creations is a great guy to do business with and you will find that he is a wealth of information on crossbows.
Bob