I flew both. 15 years on 737 300/500/700/800 and now nearly 5 years on A319-21. I am comfortable in both, although i have to say i have not yet achieved the same level of knowledge with the bus that i had in the 737. But that is to be expected. I still miss the superior avionic capability of the 737, but enjoy the better automation of everyday tasks in the A320. All in all, as an everyday workplace i would prefer the A320, although of course a mix of both worlds would be even better. Pros A320: bigger flightdeck, bigger windows, better view, better automation, a table (and yes, that is a huge difference). Pros 737: better avionic, bigger screens, more capable autoflight system if one has the fail operational system.
That said, as above, at the end of a normal working day and after 4 sectors i am less tired flying the bus, which of course would enable me to function better in case something happened on that last sector.