I have had a 14' Lavro and a 16' Lavro. I don't see any advantage to having a 14'. The 16' rows easier, more room, manuevers better, and easily fishes 3, etc.
The 16' I have now (lazy drifter) I have had for 12 years, sat out in the sun part of the time, banged down over some (Many) big old rocks, fished hard and people still ask if it is a new boat.
I have followed guys down the upper Sol Duc at 7 boards+ who were in a Guide model High Side Koffler and the Koffler definately tracks better when manuevering. Glass boats are easily over-steered in more technical water.
I would still go with the glass boat, pay a little more attention in the technical water, have a warmer ride, never get hung up on a rock in shallow water etc..
One exception if I was a plug pulling junkie I wouldn't even consider a glass boat. The bit about over steering is really compounded if you are pulling plugs all the time. A glass boat is a lot harder to keep on track when pulling plugs.
Either way you'll never regret getting a drift boat.
Word of caution though, things happen fast on the river when you make a mistake or something breaks (like last year when I was dropping into Oxbow and my oar broke right at the worst possible moment).
Always:
Have an extra oar you can grab and install in 2 -3 seconds. (saved our bacon)
Carry an extra oar lock
Carry an extra anchor and rope
Always wear a floataion device
Always make sure you can get away from your anchor rope
Get information about the river you are going to drift and if you need to follow someone down stretches of river if you don't know them or you know you are in over your head. But for gods sake after you follow them don't cork em.
Have fun, its a great way to spend your day.