I've never had a problem with transmitters that used 4 single cell AA batteries. In fact I've found it to be an asset.
But to your original question, if it were me, $50 one way or the other, I'd spend the extra $50 if I could. "Better"? They're both going to work. "Better" is what you define as better. I can guarantee one thing, the manufacturer designed and built either one with one thing in mind. How cheap can they make it and at what price point can they sell it. $50 is the difference.