The thing I don't like about the 650 is the time it takes to change from small primers to large primers. I've been considering buying a 2nd 650 to have one set up for each. Now I think I'll get a 750. I spoke with Dillon and they said that they would eventually sell a stripped down version of the 750 missing the parts that are compatible with the 650. I think I'll wait for one them.
They also said that In a couple of months they'll have an improved index block with the roller and over travel stop for the XL650.