The product page for the 3DR radios is full of bogus specs! Could you please post the REAL specs?
For example, the page claims "Receiver sensitivity to -121 dBm". That is the spec for the SiLabs chip radio. HopeRF lists the specs for their radio module as significantly less sensitive, and obviously you can't obtain the spec of the module when used within another product, like the 3DR radio.
Also, what's with the range claims? I see you've changed it at least once, but why not make a realistic range claim. These radios should do around 8 km. So why only say one or a few? Have you really not properly tested them over a few km?
Also saying "with Si1000 8051 micro-controller and Si4432 radio module" sounds like the product page writer may not have a good grasp of the hardware. It has one Si 1000 radio chip in it. I guess you can argue that statement is sort of true, but it certainly could cause someone to misunderstand and think it has two chips on board.
Don't take this as a rip. I just see a lot of radio retailers out there that either flat out lie about the specs or have such a poor understanding of the technology that they mistakenly put wrong specs. I don't think DIYdrones is either of these, so I thought I'd offer some constructive criticism to help you guys get going.
I also kind of feel responsible since I recommended using these chips in a radio design in several posts last Sept.. So if you need any help, just ask.