The main drawback at the moment is that because there is no “web access” built into the Galaxy Gear, even if you install Chrome, Dolphin or one of the other dozens of browsers available via the Play Store you won’t be able to use your device to access the web … yet.
Using a smart watch as anything other than an accessory is an interesting concept which for now doesn’t have a lot of practical use, but it was always going to happen given the Android platforms reputation for openness.
The process boils down to enabling USB debugging on your Galaxy Gear, then using ADB to install APKs on the smartwatch.
Ars Technica has have managed to get a number of apps running (including the extremely popular Candy Crush Saga) and drop video files onto the device, which works as you would expect:
Does this development pique your interest in the Galaxy Gear, or does it make the device look like more a hacker device than consumer?