Looks like aws just launched P3 instances. You can read about them here. https://aws.amazon.com/about-aws/whats-new/2017/10/introducing-amazon-ec2-p3-instances/
Anyone have an opinion on them and/or know their per hour costs?
Only a few regions have them; try Oregon to see prices. Three sizes, $3-24.50/hr.
They are very cool…IMO, the smallest is p3.2xlarge is 3$/h on demand and ~ 0.41$/h on spot (us-east-1). But it is V100 and require CUDA9/CuDNN7, so will require update respectively framework stacks.