If you acyually read my post, I haven't slagged anything off except a distributor and a gun that I do own.
I also go on to mention that another gun that I own is in the same price range as the one that the OP is talking of buying.
In doing so I am providing some unbiased information for the OP to consider in waying up all of his options.
I do however agree that I cannot comment about the AR 20 from my experience, other than to say I believe they are pretty accurate based on seeing someone else shoot one.
As far as getting parts, I don't personally think that buying a gun with parts not readily avaiable locally is a great idea, that is just my opinion and to others it may be of no concern at all.