I've flown them both, bid whatever will give you the best seniority progression in the base you want. On the FO side, thats "probably" the 73, YMMV.
I've done MIA-SEA on the 73, not really that much more painful than doing it on the bus would have been. I'd be around 10% more senior on the bus in my base, but thats not worth another long course and a seat lock to me, so I'll continue to suffer on the 73.
For the "my tray table" crowd, the very super 80 had a fold out tray table before the bus was even a gleam in that frenchman's eye.