The support was great and helped us in a timely fashion. We did use a lot of online forums as well, but the official documentation was an ongoing one, and it did take more time for us to look through it. We would have probably chosen a competitor product had it not been for the great support
Redshift support is seamless. The system is MPP (distributed), so it is highly available, always backed up by AWS and you can also have read-only replicas (at a cost) which help overcome the number of connections issue.
Although, AWS looks like is not going to upgrade its storage engine to the newer version of Postgres which is a big pity.