Range okay, okay handling. I have never run the batteries run out, because I had always put the transmitter in a small plastic box in the backpack under.
For identified problem:
Since I also use quite a long exposure times, I have noticed that has arbitrarily released the shutter at some point after about 4-8 minutes of the recipient.
I also could not detect a pattern, when and why the trip was interrupted time.
But who does not extreme exposures, thus is quite happy to be (price / performance))
But basically do exactly what you want. Dependable triggering at long range radio.