The chip and programmer each have their own advantages and disadvantages-
With a chip-you can select a different program or "tune" on the fly-with a flip of a switch.
You are stuck with those tunes however, until the unit is sent to the tuner for re programming and sent back to you. Also-the chips have been known to develop bad connections-it can happen.
With the xcal (or programmer) you must switch the engine off to load a different stored "tune" , but it will also analyze data -and read trouble codes.
Not to mention, to modify or load a new tune requires only an email.
I am swayed toward the xcal--
As far as James Henson or jah81592 as he is known around these parts, send him an email or a PM, find out for yourself.