So I use http://mor.ph for deployment of my Grails applications. The development account was great, fantastic to deploy to and try out your application. I didn't realize this transformed (database and all) into your deployed site otherwise I would have held it in dev mode until the customer had set up all their data, but then I wouldn't have discovered some other problems... Like that since you get two app servers, and it load balances, it serializes session state (how often, I don't know). But as I use the Acegi plugin for Grails, it generally (definately in my case) creates a User object - which isn't serialized..... Which means I have been getting persistence errors all through my logs.
Of course, I thought I had solved it with just User and Role, but I forgot I embedded an Address in there as well, and it would need the treatment. Wouldn't it be great if these sites gave you a bundle you could run in a VM on your own machine to mimic their deployment so you could fix your issues before you swap from single server, single db to the full cluster of mor.ph? Oh well, it is a great service in any case!