I was flying by line of sight last weekend at a local university (Yes we had permission). The front of the school is heavily wooded so lots of obstacles. Some trees are more than 100 feet. My cameraman asked me to slowly ascend up a 100 foot tree. So I would not hit the tree I did it by line of sight not FPV. However, line of sight is difficult to tell when your at the top of the tree. My FPV ground station was setup 50 feet from me. As I got to the top of the tree my cameraman's video signal cut out due to interference. He normally will let me know if i'm at or above the obstacle but not this time. The ship got high enough that I had line of sight control issues. It then began moving beyond the tree (other side) and out of visual contact. HOLY SH*T! I then activated position holding. I then heard a familiar WOOOSH (the sound of props fighting the air). Still out of sight I was convinced the ship was coming down. "This is it" I said. Then It inched its way back into view above the tree at 300 feet! I then used GPS slewing to move the ship back towards us and slowly lowered it down. I landed it and then I laid on the ground for a minute. I confirmed the altitudes later from the FPV recording and OSD. The point of my story is the GPS works very well for me with 4.8 and an external mag. I've been flying this particular octo for 100 hours now and it has been 100% reliable. I use the GPS to take the workload off me when my cameraman needs me to hold for a moment. If I'm flying by FPV and beyond sight distance I use the RTH to help me out. It always works for me. Its unfortunate it doesn't work for others. I have a identical sister ship with the same setup and GPS performs flawlessly.
http://vimeo.com/77811975
http://vimeo.com/77811975