The most common load in my 650 is the "classic" 2.7 grains of Bullseye under a 148grn HBWC for 38 SPL. With the optional x-small powder bar, the Dillon measure is significantly more accurate than my Redding BR measure running the pistol powder metering insert.
And I concur with all the others - get the case feeder, and extra primer tubes.
And be sure to get the spare parts kit! When a spring goes sproing, you'll be glad you have the spare parts!
The tool-holder with the wrenches is a nice touch - but I had to mod the mount a bit to get it to fit with the ammo bin. Keeps the stuff organized and handy however.
If you are ordering from Dillon, check out their plastics - ammo cases, bins, etc..
The following are my opinions:
I wouldn't bother with the roller handle, it forces your wrist to be horizontal through the stroke. I like the ergonomics of the standard knob handle better, allowing the wrist to be at a 45 or so.
If you have sweaty hands and find the knob un-comfortable to use, put a sock over it.. SERIOUSLY!
I prefer the Dillon powder check for my application - it let's me complete the stroke, then deal with the powder issue.
I don't like the idea of binding up the press when the powder charge isn't correct, like the RCBS Lock-out does, and then having to back off on a stroke before it is complete.
I find I get all sorts of SNAFU's if that happens. But I'm putting tiny little powder charges in a big case, seating the bullet flush, and then putting a crimp on it. And I don't trust myself to visually inspect every case.
I also have a bullet feeder on it, and the sweet spot is 20/min. Stuff could get bent or broken if/when the press binds up at that rate.