Re: whats the dif, garrys mod
Garrys Mod 10 is much better.
Instead of shooting a crossbow to add tools, you have a "Tool gun". You have many many more options to choose from, more tools, better control over the tools, and the ability to add plugins, new maps, new NPCs/characters/objects, etc.
If you want a list of differences, just do a google search or something. I REALLY recommend G-Mod 10 though if you like building things.