This one is at the top of my list for many reasons. First of all, they invented a system where you can simply buy weapons from a PDA and receive them in an instant. No worrying about hassles at customs with their heavy duty weapons.
The company enters my top-tier shopkeepers simply because of their humor about what they sell. They are off-the-wall when it comes to talking about their products, as well as the types of weapons they have created. From Decoy Glove and Morph-o-Ray (which morphs enemies into chickens) to the much-sought-after RYNO series of firearms, this company has it all. An example of this humor:
"Gadgetron has vendors conveniently located on all inhabited worlds, and also in the entirely unhabited bogs of Trachea Five. We don't really know how that one got there. Engineering blames marketing, marketing blames legal, and legal has been at a "conference" on the tropical planet of Bahamia for the last six months and they do not return our calls."
Destruction and humor, all rolled into a nice, clean package. It's been my favorite supply shop in any game series, and has made its way through all the games installments, even if just by mention alone.