InProc is best when:
1) You don't have a lot of simultaneous users (1000+)
2) You don't have a server farm
3) You don't have a lot of data to store per user
Out of Proc (StateServer) is next best when you exceed the above
limitations, but:
1) Your "session stated" data is not that important to need SQL
persistence.
2) You don't mind losing the data if the server restarts
3) You need faster performance than SQL Server gives you
Out of Proc (SQL) is best choice for out of Proc because:
1) SQL Persistence gives you reliable storage
Keep in mind that the performance goes from (best to worst)
InProc->StateServer->SQL
Steve C.
MCAD,MCSE,MCP+I,CNE,CNA,CCNA