Statistically, you have about a 10% less chance of getting a mare in foal with frozen. That said, if you have a fertile mare, and are willing to take a wee bit of a chance, the frozen option is enticing. It also eliminates the need to order and get fresh semen delivered at the appropriate moment. I just love having the semen sitting in a tank at my vet's place, waiting to be inserted at the precise time. However, when you don't get a mare in foal with a dose or two of frozen, and had no LFG, a big chunk of change goes down the drain. Because I love the simplicity of frozen, the few stallions who offer the LFG option are enticing, but I confess I haven't ever purchased one of those breedings.