On the subject of flight directors; In a perfect world each aircraft would have both. The dual cue is more accurate and I would use it to shoot an approach. The V bar is better in the enroute phase because the pilot instantly knows the full command (i.e ten degrees up and thirty degrees left.) while on a dual cue display the pilot has know idea what the final command will be until the aircraft is there. With the V bar the pilot can start turning/pitching while still looking outside/elsewhere. With the dual cue your attention must be fully on the flight director.
With respect to the 320/73S; I went from the 73 to the bus to the 73 and back to the bus. (no NG experience though)
I like the 73 FMS and VNAV better than the bus. The start down feature is better and the fact that the VNAV remains engaged when the aircraft goes into heading mode is nice. The glass in the 73 is easier to see than the bus glass. (300, though I assume the NG is even better.) You can always read the 73 displays while the bus display more often than not gives you an excellent indication on the condition of your shirt and tie.
The bus is much more comfortable. For airconditioning comfort from best to worst the fleet looks like this; NG737, bus, 737-200, 737-300. (I have jumped on the NG enough times to rate the cooling as best of the four.)
The bus, especially if you are in a newer one, is the most quiet. After three hours in the 73 you feel much more beat up than you do after five in the bus. I think the noise is the biggest fatigue factor. As an aside, after a 73 trip my shirt was usually dirty and lots of black stuff came off of my hands when I washed them. Your hands and shirt stay clean on the bus.
The size of the flight deck is another comfort factor. One reason I made the last move off of the 73 was because I was afraid my company would order the NG and I did not want to be in a 73 for five hour legs. The room and the tray table are vastly superior to the small space of the 73 and I am relatively short. I can't imagine six footers and higher wanting to wedge into the 73 over the bus.
I prefer thrust levers that move but I never saw anyone use the autothrottles on the 73 unless it was an auto land. I prefer manual thrust to autothrust on the bus but my company wants us to use it so oh well.
One of the biggest factors is how your company makes you fly airplanes. In my world the 73 department is like a completely different and much better run airline. The bus flight standards department is terrible with lots of technique as proceedure instruction from the check airman.
Bottom line is schedules but assuming everything is equal I would choose the bus. The boeing is not built any better than the bus. (just look at all those vortex generators on the 73 tail and tell me that it is a superior design.)
No one would buy a car that had the fit and finish of either a boeing or a bus. Any lexus is put together whith much tighter tollerances.