I haven't tried it, but I looked at the Gud line online and wasn't super impressed with the ingredients list. The three varieties all have highly similar ingredients, mostly plant extracts as far as I can tell, along with some sunflower oil, plus cetearyl alcohol and glycerin (like GFTN has). To me, they didn't seem like a good candidate for a GFTN replacement, but that's just me looking at ingredients and thinking "not enough good oils, probably not moisturizing enough".
CG since 11/2011
2c /3a F /Mii, low porosity

Spring Products /Routine:
Clarifying: Herbal Essences Tealightfully Clean
Low Poo: Renpure Luxurious Argan Oil
Co-washes: Suave Naturals Tropical Coconut or Daily Clarifying
Tresemme Expert Selection Perfectly (un)Done, Cure Care, Suave Tropical Coconut or Daily Clarifying
LI (if needed):V05 Kiwi Lime Squeeze, V05 Strawbery
Renpure Brazilian Keratin Straightening (old formula), Cure Care
Stylers: LALSG
PT: IAGirl's as needed