If you look up the 'side effects' of prescription HGH which is what I am taking you will see a bunch of a good sides and a few potential bads. I am yet to feel a damn thing but I have never exceeded 3 IU. My goals are different hence my dosage is usually 2 IU.
I don't look at HGH as giving me a lot of growth but it helps me heal and prevents injuries - if I can workout (I'm in my 40's and get injured all the time) for 3 months in a row two days on and one off, I make excellent progress. HGH helps with the wear and tear I put on my body.
The negative is it like
@3ml said - F'n sleep. If I get 5-6 hours I am happy. Your not imagining it - maybe some guys get better sleep but not I. Is it worth it, to me it is as I recover quicker and inevitably won't need to take as many deload weeks or take 3-5 days off to make sure I am 100% ready to start up again (feel worn down and will get injured if I keep with progressive overload).