I own a Steyr and have shot one for quite a while, I have also had a AR20, HFT500 and FTP900. The 500 is the closest to a Steyr in balance and weight and the accuracy of mine is actually better then my Steyr.
What I like about the 500 is how simple it is, the knock open valve gives me a 5fps spread and about 80 shots from a fill. Personally, the 500 is the way to go for me.
I hav just got a Goldstar, but I have not tested it yet, so I can only speak about the guns I have experience of.
Somehow I made TEAM ENGLAND 2012 and 2013
Illiterate writer for AirGunner
The real Kung Foo Panda.