Nah, I'd rather be a 737 captain than a 747 FO. Of course I can hold 737 Captain in MCO and within a year of holding MD-88 Captain in NYC, but that'd be a monsterous commute from PHX.
After your first few months online, the plane doesn't matter as much. When I first got on the 737, I thought I was the king of the world until I realized how slow mach .72 is when you're flying the last leg home in a headwind. The MD-90 is tremendous aircraft and fun to fly with the EFIS/FMS, but now I'm hooked and can't read a enroute chart worth a crap anymore.
Plus, as FO, you have to play chameleon during the trip. There's nothing more unnerving than trying to determine what the captain is going to be like.
Most guys are fantastic to fly with and it's 99.999% awesome. Unfortunately, there's always that occasional guy you fly with that is on the 'boorish' side and doesn't understand that he's not the hot shot maverick he thinks he is. You know, the "hey son, lemme showya sumthin'"-type
I think it's best said that once you're captain, you no longer have to worry about getting along with the monster in the left seat.... You ARE the monster in the left seat!!
My crown, my sceptre and my robe please!