The concept behind the G-System is great and TC Electronic really worked hard to get it right. I really like the quality effects. BUT it is my hope that they will release an upgraded version someday. I would buy it the day it was released.
There are inevitable challenges setting up the G-System simply because it tries to do so much. Be aware that it is a commitment. It requires plenty of cabling (plan on spending money on this) and effort to get it setup the way you want. You will find yourself tweeking such things as input gain, loop levels, boost level, etc. Also, many people have struggled with the advanced features such as channel switching.
It's a great and powerful system but I strongly recommend that you read the TC Electronic bulletin board before purchasing.
I'm not an expert on tone or anything, but you can hear me using the G-System on YouTube. Do a search for the band Fayrewether. I am in the more recent videos.