I don't have comparison pictures but, have seen and used some of them (as a civilian).
When you look at night vision, be aware of a common gun show trick by unscrupulous "dealers". They will take a poor quality night vision set and turn the gain up on the tubes. This makes it look brighter but, you are going to burn the tube out much faster. Since most people don't really use night vision much, this isn't a real issue for the person who sold it. If you do use it a lot, can you even find them if the night vision has a warranty?
A good Gen 2 tube will have much more light gathering capability then a Gen 1 tube - the term "Night vs. Day" comes to mind. Withing a single generation such as Gen 2 or Gen 3, the numbers of Line Pairs and gain are key differentiators.
Do you have links handy for the 2 products mentioned?