I just switched my dog over to Nexgard after the vet recommended it. First trip out she picked up 2 ticks. By the time I found them on her at the house they were already dead. Just brushed them out and she was good to go.
They need to bite the dog before it works, but the ticks die withing 10-15 minutes. It wasn't significantly more expensive than the advantage that I was using for just fleas.
Andrew