The Pro encoder is a Dolby Certified encoder while the studio version is not. The Pro encoder works on Blu Ray while the studio encoder does not. I'm also pretty sure the studio encoder will not put out a top bit rate either.
Long story short... if you have the option to choose encoders.... then go with the Pro every time.
Pro always, Studio never. The Studio version has a phase shift bug that has been duplicated by Sony, but never fixed.
That being said, the Pro encoder default settings are less than optimal. Create your own template along these lines:
I've run some exhaustive tests with calibration test tones and done extensive reading of the Dolby metadata specs, and in reference to your question about the most accurate reproduction with the AC-3 Pro Encoder, I am prepared to make the following recommendations with notes:
Go with musicvid's preset, it is how I run all my DVD's and I've run hundreds and hundreds out of my room with great results and no problems.The biggest problem with the supplied presets are the volume settings which this preset takes care of with the -31 dialog norm.