Im a little confused?

Well, with a multi-fx, you get multiple effects. However, a Boss Chorus Enseble pedal will offer you a lot better, much more versatile, chorus then the one found in most multi-fx units. The wah of multi-fx don't come close to real wah pedals. The digital distortions are often pure crap.

You get a lot, but it is of lower quality. That is more or less what its about. Ofcourse, when you buy a 600$ multi-effect the quality if pretty high :D

Ok, that all i really needed to know.
Thanks for the help ;)

I dunno....a couple of the wah sims on the GT-6 pretty much nails it

It comes down to the fact that a multi fx unit can gain many synergies as against the dicrete nature of individual pedals.
Let's say that you have 4 pedals (what they are doesn't matter).  You have 4 housings, 4 switches, 4 power supplies and 4 circuits on 4 discrete circuit boards. They are not programmable and each can be turned on and off by pressing on the switch.
A multi fx unit puts everything into one housing with one power supply - we already have a major cost saving here. The multi fx unit makes use of integrated circuitry and programmable chips. There is another cost saving here - it is cheaper to produce one board with ICs than 4 discrete circuit boards (each one needs it's own production line).
However this is where the lack of sound quality also comes in - you can use high quality components on a high quality PCB and put different types of component in to change the sound (changing from a standard diode to a quality germanium diode wil change the end output).  The multi fx unit uses effectively a computer program to generate the sound - think analogue against digital. If you are a hifi buff you will know that analogue produces far more "realistic" sounds than digital.