I have had experience with both. My 66 Hemi Charger back in the day when it was driven regurlarly was very fast, however, my 71 GTX which I also owned at the same time, was quicker off the line to about 50 mph or so.... after that, the Hemi would just blow by it. The Hemi would keep pulling well past what the GTX would, and while I topped the GTX out at a shade past 130 (indicated), I never did have enough nerve to find out where the Charger would quit. The GTX was a 440 4speed with a 3.54 Dana, while the Charger is an automatic with 3.23's in it. The Hemi's were notorius for being hard to tune properly and keep that way.... doubtless the comments that they didn't run all that great stemmed from someone's personal experience with one that was neglected and improperly tuned.