Yep. I had been hesitating on moving more domains over to Route53 because I thought the per-zone pricing was fixed at $0.50 per domain, but it actually scales really well. I'm going to move the rest over to Route53 as soon as I have a chance.
We're using Route 53 in production to handle hundreds of millions of queries per month. We're happy with it, and the price is reasonable. Also, service checks with failover is heavenly.
$0.500 per million queries – first 1 Billion queries / month
$0.250 per million queries – over 1 Billion queries / month