Having developed in Siebel for over 13 years, Siebel/Oracle CRM OnDemand for 3-4 years and SFDC for 6-7 months. You made the right decision. Oracle CRM OnDemand is a useless piece of junk. If it can't solve your business requirements OOTB it basically never will. It has absolutely no server side code support and the client side JavaScript is limited to only 1500 characters. You can however include your own javascript files but you will need to host them on another server, which kind of beats the purpose of using Oracle's hosted environment in the first place.
If you are using Oracle CRM OnDemand I here from good inside sources that there is no upgrade path for any custom configurations at all to the planned Fusion CRM platform. Apparently your data will be migrated but no configurations.
Now I don't believe that SFDC is the greatest thing that I have ever seen, but in comparrison to Oracle CRM Ondmand they are not even in the same game. Do yourself a favour and switch to SFCD, if you haven't purchaed Oracle CRM OnDemand, seriously don't waste your time.