Purchased a Tritronics G3 Sport Basic over the summer and have been very very pleased. Far more stimulation levels than my girl requires, waterproof receiver and transmitter, and a half-mile range (again, far more than required). The transmitter can even expand to 2 additional collars.
As far as charge goes, we probably have it "On" for a few hours a day while we're out in the woods walking, running or training and I've routinely gone 2-3 days without a charge, and have never seen it run out.
Would definitely suggest it to anyone looking.