Has any had some first hand experience with the American Spirit Arms side charger AR upper receiver? I've been looking at building another AR but the cost on these is steep. The prices I've seen for the upper alone is in the $300 range. And that's not even with the bolt carrier and bolt.

So if I could get some feed back on it from a user, I would appreciate it. How's the ergonomics of the charging handle? It looks like it would be a major step up from the rear charging handle. Is it mechanically complicated? How is it for tear down and cleaning? Etc, etc.

Thanks in advance.