Like everything there are pros and cons
I've had my 14' VG for 6 years, been down the Grand in it, boated plenty and it's holding up great. Only problem - its kinda dirty and needs a good cleaning and some 303...
Do a search on Vanguards and look down below the quick reply box for similar threads, you'll find plenty of information.
You'll also find that some people say that glued PVC boats have problems inherent in the production. This was the case 15 - 20 years ago when they first came out but the problems have been dealt with and they're great boats.
Nothing in the world is more yielding and gentle than water. Yet it has no equal for conquering the resistant and tough. The flexible can overcome the unbending; the soft can overcome the hard. - Lao Tse