Field stripping and cleaning, no, but if you want to do a detailed cleaning of the rifle you may have to.
As for your question about free-floats, when you shoot a bullet through a barrel, the barrel oscillates (a giant word for basically vibrating from the spinning of the bullet) if this process is interupted by a fore-end it can change accuracy, not significantly enough for the average Joe hunting white tail at 50 yards to notice but it helps to squeeze out as much as you can. This is more prevailent in wood and cheaper plastic stocks as they like to expand and contract with hot and cold temperatures and moisture.
This free-floating process on fore-ends of guns is common on bolt actions and is one of the main reasons they are so accurate.
So in a sense the free-floats are better accuracy wise, BUT if you're just looking for an OK fore-end for an AR there are free-floats that dont cost $200 but all the one's (including the JP Enterprise's one) I've seen usually require minor fitting and gunsmithing and if whoever is installing if for you, whether it be yourself or someone else, make sure they know what they are doing.
A drop-in is not a horrible way to go if you want to save some money but it does cut down own your longer range accuracy like every other non-free-float fore-end.
One of those things where you have to weight the pros and cons for youreslf.