Need Opinions - Rebuild 904 or Move to 727?

Guys, need your opinion here... I've been told by many shops to stick with my 904 and rebuild it, and I've been told by equally as many shops to trash it and go with a 727.

Car: 1970 Dart Swinger

Motor: 408 stroker; +/- 400 HP & TQ

Driving: Mostly daily, occasional track use (likely 6 times a year)

Stall: 2500 Hughes

Rearend: 8-3/4; 4.10 gears

I honestly would like to keep the 904 as it is the transmission that came with my motor & driveshaft and would likely result in less gray areas during the swap from the /6 drivetrain.

Is it worth rebuilding my 904? Or should I just go with a 727?

To the guys with similar numbers, what have your experiences been with a well-rebuilt 904? If I stuck with the 904, I'd want to get a RMVB installed to keep things fun... Any foreseeable issues with that?

Thanks for any usable input fellas!