If you chain them in a propper way, you should be ok.
As long as all jacks stay clean and you use quality material I see no problem.
The only thing you have to keep in mind is that the sound can change depending on the order in which you chain the different effects.
For example, chaining the distortion before the wah, gives a different sound than chainging the wah before the distortion.
In the first the wah's input signal is a distorted one, in the second the distortion input is a wah wave. It can really effect the sound.
If you use pedals in a chain, it is hard to change this order while playing.
Using a GT-6 you just create sounds and program the order you want the effects to be in. Depending on the sound and the effect you want, you can just change is arround as you are playing.
The GT-6 has 15 distortion/overdrive modeling types and 5 Wah modeling types.
Combine this with all the other features and You will be suprised what sounds you can create.
it's just a question of personal choice. I decided to buy the GT-6 because it has all the effects. I knew what is was going to cost me but also even if I didn't use all these effects at this moment, the day I decided to try them out, it wasn't going to cost me any more money.
Don't want to make it any more difficult for you to decide, but if the price is the same, I would certainly go for the GT-6