Probably preaching to the choir, but I just want to acknowledge that investing in good batteries is one of the best things you can do for yourself. Back in early 2013 I bought 3 sets of Freefly 9000mah packs and have used them solidly for 3 years, totaling around 900 flights. That's about 300 cycles each. Only now are they starting to really show their age and sag in voltage, but I still get a comfortable 8-10 minutes out of them. In contrast, the most use I got out of the turnigy packs I had before that was around 50 cycles or barely even one season. And- those turnigy packs let me down on several occasions by suddenly losing all their juice/ several dropped cells and were unusable even before 50 cycles. Plus, I had to redo all the connectors to switch to ec5 first thing after purchase. Every single "incident" I've had that caused an unexpected "landing", (events that are bound to happen if you've been doing this long enough) were caused by battery issues. My Freefly batteries have never let me down, and even though the whole bunch costs a bit more than you can buy a full phantom 4 setup these days, they are well worth the money. If you are flying a big rig, batteries are the very last place to try and save some money.
Good points, Tim. Restating the Second Law of Bistromathics,* "Youse get what youse pays for." See http://hitchhikers.wikia.com/wiki/Bistromathics Andy