Govino versus GSI ...
For drinking and comfort in the hand, the Govino glasses are hands down the better glass for enjoying a glass of wine, scotch or beverage in general. They're more comfortable and I like how they flex and give a little bit. Real stemware you'd enjoy with a nice bottle of wine out to eat or at home isn't thick, it's slender and has a nice bit of elegance to it. Keep in mind, the Govino were designed originally for wine tasting events because wine makers couldn't travel with traditional stemware. So, created by wine lovers for wine lovers. See the NY Times, SF Chronicle, Wine Spectator, etc for press on them.
For durability and long term use, the GSI (plastic version so we can compare apples and apples here) is a heavier/thicker material and will probably take more beating in the long term. However, I hate that plastic/lexan material they (and other companies) use. In the long term, under heavy use, it has become brittle and looks like hell after it's scratched up from being packed in a bag and rubbing against other gear.
So, I think the greater question is what works best for your particular application?
If you're going to use them every now and then, then the Govinos should be fine. If you're going to throw them in a pack and use them long term for longer trips, grab a set of the GSI stemless.
The Govinos can be recycled after you've gotten your use out of them and they're inexpensive to replace. At roughly $3 bucks a piece (they come in a set of four for $12, which will go up to $13 on May 1st), I'd rather have two glasses for the price of one of the lexan/plastic GSI versions.
If you want something indestructible for long term use, you shouldn't buy any of them. A $3 or $7 glass is simply that - an inexpensive glass. You need the Snow Peak double wall titanium nesting mugs ...
http://www.snowpeak.com/ti-double-h300-stacking-mug-tw-123.html
It's "stemless" and you won't break it unless you run over it.
Hope that $0.02 helps.
Give me a call anytime if you want to chat more about wine, glasses, or the most important aspect of travel ... food.
Cheers!
Zach