There are two aspects to quality supplements.

1, the ingredients, and more importantly the form of the ingredients, used.

2, Added "other ingredients" such as fillers & binders or certain flow agents such as magnesium stearate in our opinion lead to a lower quality product. 

In formulating GÜD vitamins the goal was to provide the most bioactive forms of the vitamins without added fillers, binders, etc. Bioactive forms require little or no conversion in the body and are thus more easily and efficiently utilized (thus yielding superior health benefits).
As a result we have added the following

1) Benfotiamine a bioactive fat soluble form of thiamine which has an increased absorption rate to thiamine and has shown useful in neurologic conditions
2) Citicholine (CDP-Choline) - a more bioavailable form of choline, helping to enhance brain health
3) Most bioavailable forms of B vitamins including Riboflavin 5 Phosphate (B2), Pyridoxal 5 Phosphate (B6), L-5-methyltetrahydrofolate (5-MTHF) (folate), and methylcobalamin (B12)
4) Both Vitamin K1 and K2 (menaquinone K7) are the most bioavailable forms of vitamin K. These helps bone health as well as having cardiovascular benefits
5) We opted out of using citrate forms of minerals as they are derived from fermentation of sugars with aspergillus niger (a mycotoxin forming black mold). We feel the malate, picolinate, and glycinate forms of minerals are preferable as no molds are used in their manufacture
6) We avoided using calcium carbonate, since it has very poor bioavailability and absorption vs other forms of calcium such as calcium malate.

What we NEVER use:

Many supplements add "vegetable stearates" or "Magnesium Stearate" which is a lubricant to help speed up vitamin encapsulation. Magnesium stearate is generally derived from Genetically Modified (GMO) hydrogenated cottonseed oil. 

Titanium Dioxide is often added to make the capsule look "pure white". The EU has listed titanium dioxide as a possible carcinogen. 

Sugar, fake sugars such as asparatame or sucralose

Food Dyes.

Polyethylene glycol (PEG) which is derived from petroleum

and many more substances.