What I look for in a wheel:

(1) Durability
(2) Performance
(3) Ride Quality

If you are already beating your friends up hill with heavier wheels then peformance isn't the issue, however a deaper section rim could make you faster going down hills. But, good wheels are not cheap. A set of Zipp 404s would probably cost you $1800+ is it worth it? There are cheaper options such as Reynolds. I wouldn't worry about getting beat going down hill. The challenge is going fast up hill and you are already beating your friends in this department.