What would be recommended node for elasticsearch Cluster

My ES cluster is running on AWS on i2.xlarge(ubuntu) five nodes. Current version is 1.1.1. We want to upgrade ES cluster. We have decided rather than updrade create new cluster on AWS. I have muiltiple question:

  1. is the current elasticsearch version i.e 2.4.0 stable for AWS?

  2. is the current node infrastructure ok or should we go for "M3.2xlarge" as mentioned in this blog ?

  3. according to the blog mentioned above, it is recommended to use "Amazon Linux AMI 2016.03.3 (HVM), SSD Volume Type". What are the advantages that Amazon Linux provides over "Ubuntu Server 14.04 LTS (HVM), SSD Volume Type " ?

I would really appreciate any suggestions.
Thanks.

What do you mean for AWS? We don't provide AWS specific releases.

Depends.

The Amazon AMIs contain tweaks for their system, so it's more efficient.

Thanks @warkolm