Tub Wall

Bath wall, the difference between a piece of 1 and a multi-room?
I have to buy a kit tub wall. What are the differences between them? Less work, better!
I put a lot of these things and in my opinion, around one-piece should be used when building cavity of the tub / shower from scratch. Are made to fit the opening of a fairly accurate and if the walls are finished, for example, 1 / 4 "different in length than the size of the envelope, which does not meet properly and therefore look just awful leak or not work at all. Of course, once you buy and try saving, and becomes unreturned you own. The three units of work are simple to install and adjustable in length and depth. Just use lots of glue and have a smooth surface and better able to mount it.