Not especially. What you do get is:

- SSL for "free"

- If you use Route 53, it's a single DNS lookup (no CNAME hop)

- If you're using a VPC you can use an ELB to face the public Internet.

- (Slightly simplier) auto-scaling.

- Redundancy across AZ's

Many/All of these things you could achieve yourself, but if you were using EC2 resources you'd probably find it reasonably expensive.

The redundancy across AZ's is limited to the removal of the zone from the ELB config if all the instances from that AZ are marked as failed. If the API is down, tough cookies. All you get is 503 errors for each request hitting the failed AZ. Asked the support to implement proper failover. They said they're working on it, but no ETA. Didn't see an announcement about it in the mean time. Their resolution for closing the ticket was: "script it yourself" with the core assumption that the API works.

I say these because I don't want people to get a sense of false security when deploying to multi-AZ behind ELB.

The other thing is performance. It's almost impossible to get the same performance as the ELB at similar cost.

http://blog.rightscale.com/2010/04/01/benchmarking-load-bala...