Differences between SQL Server 2005 and SQL Server 2008 deadlock handling
"Sensitivity to deadlocks" is not version-specific.  It is related to concurrency and contention.  Please see this BOL reference on more information regarding deadlocking.

There are certain things that influence deadlocking, such as transaction isolation levels, and lock escalation.  These are configurable settings that impact if and when deadlocking can/will happen in certain situations.

It will take a bit of investigation on your part to find out why you're seeing more deadlocking happening.  But to answer your question, it isn't specific to the version of SQL Server.

As for the deadlock process, when SQL Server runs into a deadlock it will choose a victim so that the unresolvable concurrency situation can complete.