I have some Rugged and a G Tech mini, all of them working nicely.
You get more for your dollar with LaCie, e.g. triple interface in all FW models and more space for the same amount of money.
The G Tech enclosure is stronger and a tad smaller, but probably less shock proof - the Rugged has the rubber bumper, a soft aluminum case and internal rubber suspension.
Mine travel a lot, and get dropped occasionaly, no problem.
The interface and HDD quality should be close or identical, though I don't know what brand each is using.
Oh, and I wouldn't get 160GB, the higher capacities are so close in price these days.