If you are just looking for some to use for dog training, I recommend you get something simple. These happen to also be cheap!
I have a pair of Cobras that I got at Target for under $50. They have lasted through 2 training seasons so far. I use lithium batteries in them, the rechargeables don't hold enough charge.
One thing I don't like about them is that they sometimes miss the first part of what people are saying but if the group just holds the button down an extra second before they speak,no problem. Otherwise they are perfect for dog training.
I had fancy ones with lots of functions. None of them lasted. The midlands I had, which some recommend on threads here, were particularly horrible because it was easy to hit the wrong button on them, and change some fundamental function that I would then have to waste a bunch of time trying to undo!
So go simple!