I use better bottles, received the deluxe kit from NB as a birthday gift back in May. Actually came with two bottles, the person who bought it for me put down for an extra secondary and NB (prob unk to them) sent not one but two extra 6.5 gal better bottles leaving me with not two, not three but four carboys. They are nice and light weight, however if you go with that kit, i highly recommend buying some milk crates (amazon.com for 6 bucks a piece, maybe less locally if u know someone) for moving the filled carboys. problem with better bottles is that they aren't firm like glass and they aren't flat/flush... they have a slight bubble or curve that goes up from the ground towards the opening of the carboy. When you pick up a better bottle, the weight of the wort inside will push the bottom bubble down ever so slightly. If your airlock or blow off hose are already in place, u run the risk of sucking sanitizing solution into the beer because when that bubble dips, it acts as a vacuum the opposite way. Happened on my very first batch and i almost lost my marbles when the all the sanitizer in the airlock shot into the wort after i pitched the yeast. Depending on what u use as a sanitizer, it prob wont affect your beer but if you go to move it after fermentation and anything got inside the airlock, such as fruit flies, u run the risk of infecting the batch.
The only con I see from Better bottles other then that back suck are the cleaning methods. U can't use a carboy brush, but need to buy powders like that PBV stuff northern brewer sells. It works great, just make sure u use hot water and slosh it around a bit and all the krausen will go, but the PBV can get expensive if your brewing alot of beer.
Either way congrats on investing in a new kit, I hope u find it as addicting as I do!