Arguing RoR is ready for Enterprise Apps you have to define an enterprise app!
1) Ruby on Rails is a super-productive environment for developing applications. It’s faster to build apps in Rails than in Java or .Net, hands down.
Well - Rails is a web-app tool, comparing it to Java or .Net is like comparing apples and oranges. You should be comparing RoR and JSF, Tapestry, Ripes (insert your favorite Java or .Net web framework here).
2) Agree.. totally
3) Again - you have to define enterprise app. I can easily point you to an enterprise app which should/and is capable of handling MORE than 11k request pr. minute (think corporate back-bone CICS like systems and you'll see WAY more requests)
4) Yes - Rails of JRuby will help the Rails fw to spread. Its the JVM platform that is really interessting.
5) Sure (I dont know - don't follow Ruby nor Rails much)
Still - Not being much of a Rails kinda guy can you easily write and deploy remote (RPC style) entities with transactional contexts (2PC) and such in Rails.. Else I declare: NO CONTEST!