I agree with johnr, one piece all the way. The only two piece rods I own are trolling rods and they are around 8 foot rods. Easier for storage and don't necessarily need the sensitivity of a one piece when trolling IMO.
Not that many years ago, rods with ferrules often had a "hinge" in the action. That's not much of a problem any more. Fly rods really lead the technology on multi-ferrule rods. Even 4-piece fly rods are very good nowadays. I'd buy a 2-piece design on any rod over 6'6", the max height of my camper's shower stall.
Every rod I have in the boats is 1 piece except for my planet rods, which are 1 piece but extendable to 9 feet. I just think they work better out of the boats, with rod lockers. That being said, I keep a couple 2 piece spinning rods in every pickup I own.
I solidly use one piece rods that require finesse fishing with lots of feel. Crank rods I have some two piece and my surf rod is a 10' four piece for easy travel. Depends on your application and use, but I'd prefer a 1 piece if possible.
i like 2 piece ones just for the ability to take them apart and lock them in the tool box of my pickup only have a couple 1 piece rods and they are all in the 5 foot range for jigging outta the boat