LOW CARB BEER ANYONE?

The thought came to me in a discussion that included enjoying the occaisional cold brew.  Lower carb, lower calorie beers.  I know they exist but I ignore commercials so thoroughly that I don't know anything more. 

Nutrition stats are searchable.  I'm interested in what you think of these beers.  Especially if you are/ were a beer drinker. 

Has anyone tried it?  How does it compare to the same label's regular and light products?  Any info is more than I already know. 

I don't actually know much about low carb beers but DID hear today that Guiness is lower calorie and lower alcohol than most beers.

I only ever drink beer when I am on vaction in the UK and visiting my friends there - and then I am a Guinness girl all the way. (I figure I can't get in too much trouble when it is an anual or bi-anual event!)