My experience with AWS hasn't been good when we had major problems in redshift becoming unresponsive. Since it was an intermitent issue and not a full blown blackout they just shrugged and we kept having problems for months.
Practically speaking keeping an eye on locks and transactions is a good idea, as is watching out for your statistics on key core columns going bad when they shouldn't. (analyze and vacuum sometimes don't actually do anything when you need them to...)