Well I can't speak for Quentin, but I am sure he will be along shortly.
RGuns has a like/HATE relationship with customers around the internet. We have never done direct business with them, so I can't say one way or the other.
On the surface the product itself (receivers) seem to be of the same or equal caliber/quality as the endless collection of others out there. They use an undisclosed aluminum, AL being common in receivers, but it doesn't appear to be named (7075 for example is listed on the sites' Delaware Machinery offerings). They list a ton of receivers with 8625 Mil-Spec coating, but that doesn't really tell me WHAT they are coating, so I am a bit curious.
They don't have a FAQ on their site, but their e-mail and phone number is clearly listed. With that, I would ask a few questions before placing an order (material, warranty, etc.)
As for around the internet I have read people that have had good customer service (with issues) and people who have had nightmares with real or imagined issues.
The products itself seems to work well with fit and finish (assembly) but seems to struggle with operation WHEN
there are issues. Reports I have read range from really helpful to outright discourteous.
Now I subscribe to the theory that if you understand the platform, and you have a decent to good quality parts list, you should be able to make it work.
I don't personally see anything about RGuns that would have me shy away from ordering if the answers on material and warranty were satisfactory and if the price was right.