Personally I think there is a place for both plastic & glass carboys. So let's consider some questions....
1) will you be making beer & wine in the same carboy? if so, get glass. Or dedicate a set of plastic for beer.
2) will you be making strong flavoured fruit wines, like the mist wines? if so, get glass. Most mist instructions recommend glass after the fruit pack is added.
3) will you be aging the wine in a carboy? If so, get glass because it is less porous to air (ie oxygen).
4) will you have trouble lifting a full glass carboy? (5? pounds heavier) if so, get plastic.
The plastic carboys are good for short term storage, they aren't breakable, & they're lighter.
The glass carboys don't absorb flavours, and are less porous to air.
Note, I do NOT accept the water jugs as a wine carboy. They may be fine, but they are designed to hold water not alcohol. Maybe I'm just conservative. Also they are usually 18.9 litres, and I need 23 litre carboys.
I currently have access to three different styles of plastic carboys. My comments principally refer to the Wedco carboys (opaque, #7.5 or #8 bung), and to the Spagnols carboy (#11 bung). I have no experience with the Better Bottles (nice & clear, #10 bung).
Steve