38 gbps, that's incredible. We regularly deal with 8-10. We use dosarrest and it's like it's not even happening. Amazing service. Recommended to us by rackspace when they couldn't help us. Expensive, but if you're a regular target, worth it.
How much more expensive they are than CloudFlare? I can't see any public pricing available on their website.
At that level, there are no published price plans - its whatever you can get someone to agree to.