We've been using a Havahart wireless radial fence for 8 years. They recently stopped making all of their fencing systems. So we are looking at Pet Safe wireless systems when we need to replace. These use a proprietary battery system, which are $$$. Our dog has been very hard on the collars, which were nearly as expensive as the whole system. What ever brand you pick, check the replacement cost.
Things we learned the hard way:
Always remember if the dog has the collar on. Poor dog got shocked lots of times when we took him on a car ride and drove out of the zone. Its near impossible to get the scent of skunk out of a collar.
If wireless, you have to walk the entire perimeter with the collar to see if there are "shadow" zones between the transmitter base unit and the collar. Again, poor dog was getting shocked cause the water heater and stove created a shadow if they lined up, till we moved the Base Unit higher up. For the first few years, while our dog was young, if he saw a deer, the collar was no deterrent even at Max High. One of the base units failed, in the sense that it would not let the dog return into the zone with out getting shocked. It took hours to figure this out, and to walk the zone and find where he was trying to get back in. He didn't bark for some reason. You always have to double check that the collar latch was entirely clicked in. Its near impossible to locate a lost collar.