Huge:
The others adequately argued the merits on the fly rod side but I have always questioned the prevailing wisdom when it comes to conventional rods. I fish a LOT with baitcasting tackle and a moderate amount with spinning tackle. ALL of my baitcasting and spinning rods are two piece for a simple reason: I don't have the room in my fishing-mobile to easily store one piece 6'-10' rods.
I have caught and landed PLENTY of bass between 4-11 lbs on these rods with zero issues, as well as many other larger freshwater fish and some real bruisers in the salt. I also only have to think about the MANY tarpon, permit, and billfish that have been successfully landed on fly tackle; not to mention scores of stripers and blues caught on 2 piece surf rods to make me scratch my head and wonder why in the world a bass or other species fisherman would think for a minute that a multi sectioned spinning or baitcasting rod wouldn't be strong?
As far as sensitivity goes; rod flex profile, rod material and construction and fishing line type have more to do with sensitivity than the number of sections. A tomato stake with braid can be more sensitive than a fishin' pole with mono. While for me; casting accuracy has always been more about the angler than the tackle.
I often times think that the lack of multi-piece tackle in the conventional arena is more about tradition, the lower price of a rod with no "joints" and a lack of storage problems rather than true advantages in performance. My buddies with bass boats really don't have a need for multi-piece rods because they just keep their tackle rigged up in the boat's rod locker or lying on deck while they're fishing. The saltwater gang has similar options so why bother with multi piece if you don't have to?
A half-cocked theory of mine regarding the "tradition" of multi-piece fly rods is that many fly-fishermen in beginning were well-heeled and subsequently had the ability to travel to fish. Since the stagecoach or train was the method before the automobile; "pack-ability" was a benefit. As a result; the tradition continues today.
Some people have a; "more joints, more problems" mentality which I guess can be valid but that's similar to a; "more options, more problems" mentality with an automobile; if you never had a problem with your heated seats, you aren't afraid to order them.
For me it's all about convenience. I'll never argue that a multi piece rod "feels" exactly the same as an identical one piece rod. But I will argue that the differences in performance are negligible or possibly indistinguishable if done correctly.
Other issues aside, you should never let strength, sensitivity or accuracy concerns steer you away from a multi-piece rod. It should be all about what works best for you and your budget.
JMHO