The AD700 is one of he best headphones for competitive FPS gaming due to it's fairly unintrusive bass and excellent positional soundstage. Unfortunately, the unintrusive bass also makes it a fairly boring headphone when used for music and film, especially if you listen to music with a warm, bassy tilt. It's size and open design makes it unsuitable for portable use.
On the other hand the CAL is a decent headphone for gaming, with a better than average soundstage(for a closed headphone in the sub $100 price point) and is a nice headphone for listening to music and movies. It's a fairly small headphone, just about fitting in the circumaural(around the ears) category with a short(3-4ft) cable, making is well suited to portable use.
Neither headphone isolates very well. The open AD700 doesn't isolate sound at all and leaks everywhere, as open designs tend to do, The CAL is below average in terms of isolation for a closed can, but doesn't leak too badly unless played at high volumes.
If you could only pick one, I would pick the CAL as it's a better all rounder as well as suitable for travel.
