I wouldn't worry, because what you are hearing is people making wild guesses
Mind you, every game on release has some folks who zip to the cap, but since they are not representative of the vast majority of players (even "hardcoe" players), it is not something to worry about I just ignore em, myself. They've made a metagame of the race to the finish, so they are playing a different game than everybody else is.
150 hours to level cap for the normal player is what people playing the longterm beta have been saying... longer for slow players, shorter for very fast players. I'm a slow player and happy about it, though I guess having played a lot of beta and read every scrap of info might (sadly) speed things up a bit for me Won't be all guesswork.
As to how long it will take to get to V10, there's less reliable info about that, but people have definitely done it in long term beta.