The first technique is good for the chromatic scale because it will give a sense of flowing into each note, rather than the choppiness of the second technique. This technique is best used when playing hammer-ons and pull-offs.
The second technique will give you more of a acuity to each note you play. The downfall is that, it can sound rather sloppy if not precisely played. Because if your pulling your finger off after the note your playing, your changing its sound by either semi-muting it or sounding the string your playing by pulling off. This makes it more difficult to control, but then again it might be the sound your looking for.
In the end, I guess it’s your call to which you use. The way you want to play something will answer it. My opinion is to go with the first technique with your normal playing style, and use the second for whenever you want that particular sound when playing.
"My whole life is a dark room...ONE BIG DARK ROOM" - a.f.i.
