I have recently been looking at using Oracle subscribers in a SQL Server 2005 transactional replication topology. The main gotcha's I have identified are that the distributor can no longer co-exist on the subscriber (as a remote distributor to offload the log reader agent processing) and propagated schema changes will cause the subscription to be reinitialised. These are fairly important factors, particularly when we are talking about OLTP and terabytes of data. There are a bunch of other details listed in BOL under non-SQL Server subscribers http://technet.microsoft.com/en-us/library/ms151864.aspx which you should be aware of.
The good news? Not much I'm afraid, apart from the fact that the Oracle 10g R2 provider supports x64 and IA64.
Just noticed a new KB article describing the RML utilities for SQL Server 2000 and 2005 http://support.microsoft.com/kb/944837 which supersedes http://support.microsoft.com/kb/887057. I haven't had a chance to play with this tool yet but it looks pretty good. I particularly like this feature:
"After you capture a trace for an instance of SQL Server, you can use the RML Utilities for SQL Server to replay the trace file against another instance of SQL Server. If you also capture the trace during the replay, you can use the RML Utilities for SQL Server to compare the new trace file to the original trace file. You can use this technique to test how SQL Server behaves after you apply changes"