I'm thinking about upgrading my 550 with the Casefeeder for several pistol cartridges.  What are the pro and cons ? Is it worth the cost ? 

I'd still like to load rifle cartridges so how difficult is it to switch back so do so ?  What has to be removed ?

I'd buy a XL650 but with 5 RL550 tool heads and 3 caliber conversions aside from almost being over the hill I can't justify it.   If Dillon had a "trade in" deal that would be a different matter..:-)).