OK normally I would tell you that the answers to your questions are easily reachable with simple googling, but your avatar has hypnotised me into being helpful
Benefits:
Gaining muscle and losing fat
Return of sexual drive, potency & pleasure
Losing Wrinkles & Cellulite
More restful sleep - help for insomniacs
Improved mood/sense of well being
Substantially increased bone density
Hair growth/colour restoration
Return of youthful vitality, energy & stamina
Improved memory, alertness and concentration
Faster injury recovery
Eyesight, cholesterol & blood pressure improvements
HGH will help you with recovery, it is recommended to run a cycle of at least 4iu a day (with periodic off days for example 5 on 2 off) for at least 6 months to see any great benefit.
I have been on HGH for only 2 weeks so cannot offer much personal insight at the moment.
It is also recommended to run test with HGH and insulin can be of great benefit alongside HGH.
If like me you do not plan to use insulin look into the effects on natural insulin levels caused by HGH, and you may consider using metformin.
This thread is very interesting in that regard:
http://www.T-Nation.com/tmagnum/readTopic.do?id=2069145
Also for more HGH info please look here:
http://www.T-Nation.com/tmagnum/readTopic.do?id=2062370
All that just for a bit of cleavage hahaha!
EDIT
I should just also add I have been told by quite a few experienced users not to expect major things and that HGH is not a miracle drug and is not as amazingly as effective as some people may believe.
A lot of the hype about HGH has been caused by anti-aging clinics that benefit financially from positive media about HGH