When i practice i always play with my thumb on the center of the neck or i guess what is called "classical style". I notice that a lot of players play with their thumb almost over the neck. They kind of have the guitar resting in the wedge between their thumb and the rest of the hand. The point i'm trying to make is that they play with their thumbs really high on the neck...I've seen Petrucci play like this and specifically Eric Johnson and Jack Thammarat.

I read in a guitar book to keep your thumb in the center of the neck, i'm not sure if it was good advice or not

I just want to know. Is my posture bad for having my thumb so low ? is it going to make it harder to play fast legato runs once i build up more speed ? or is it just kind of skill where i have to learn to play in both positions ?

Thanks in advance for your advice
i actually just finished watching that video a little bit earlier ! I found it searching through old threads. Thanks for the reply !
Really, can't we just make a sticky with all of Freepowers technique-related video's? Could save us from alot of replying