Hi mike

It's a very good question.

 There are'nt one better then the other.
The puckering is good if you use your free tongue for some articulation like: tremolo, wa wa, some tong vibrato and playing thirds and anther 2 notes together.
The tong blocking is good for playing cords and melodies in combination and making zap cords like in blues stile.
I use The tong blocking.