Before I fly anything I check. It has a great record. I could only find 2 accidents.
Still unneeded to post here, safety in an aerobatic plane such as the Edge is primarily a function of the pilot. The aircraft VERY RARELY fail, and most of the times such accidents are the result of pilot error, or the "Hey y'all watch this" Syndrome, as I call it.
Based on the narrative given in your post, it appears the pilot failed to level the plane fast enough following his 2nd hammerhead, or performed the hammerhead at too low of an altitude, and perhaps even induced a high speed stall by trying to pull out TOO quickly when he saw he was too low. The Edge, by design, can easily pitch rapidly enough to induce a high-speed stall. (this is desired for many aerobatic maneuvers).
Performing aerobatics at low altitude obviously carries certain risks with it, and should only be done for demonstration purposes. (airshows, practice for shows, etc).
I, for one, ESPECIALLY if I am carrying a passenger, will only peform aerobatics at a MINIMUM of 2500 feet AGL. I set that as a "hard deck" and during my practice, consider any excusrion below 2500 to have been a potentially fatal crash. In this way, I will learn, over time, to bring the "show" closer to the ground, to prepare for the time when I feel I am ready to begin performing at airshows and such.
Granted, I occasionally will perform basic aerobatics, such as aileron rolls, or inverted flight, at lower altitudes, but such maneuvers I consider safe, and consider myself proficient enough to perform at lower altitudes. But anything with a result of a significant descent rate, or nose down attitude, I only perform at altitude.
This will change when I have gottent o the point of practicing directly for a aerobatic routine/airshow, but ONLY when I am flying solo. I will always perform aerobatics with a "hard deck" when giving a passenger a demonstration flight.
(Please forgive my spelling, am typing one handed, as I got my hand caught in the prop of one of my RC planes a couple days ago, and have many stitches and heavy bandages on my left hand)
Sol