Since you are starting with 3 to be converted kegs, get a stand with 3 burners and a couple of pumps. Brew without either and see how it goes, and then layer on top of that palate.
I started with RIMS because my BIAB setup in a converted keg would not hold temperature in Minnesota winters.
I like the recirculating system I have in place now, but here are some of the downsides:
- more to clean (RIMS Tube, tubing pump)
- more to build
- more things to plan for on brew day, more connections, tubing, joints, etc.
I get clearer wort into the kettle, and slightly higher efficiency, but mostly I get a pretty awesome bling factor.