For PST tanks, I my preference order goes:
LP80<HP100<LP104<HP120<new E8-130.
The new PST E8-130 IMHO has a slight edge over the old LP104 and old HP120 as it is the same as the old LP104 in terms of capacity (but are service rated for the higher pressures, so there are no "overfill/cave fill" issues, such as finding someone willing to do it), but the specs I read showed that the new tanks were lighter out of the water and slightly shorter than the 104's. About 6lbs heavier and 3 inches shorter than the HP120's for 10cf more air. Don't know about the bouyency though, but I remember something about them trying to move the bouyency closer to neutral (which may or may not be good for your specific dive profiles).
And go DIN over Yoke, it's just a better connector. As long as you have the proper adapters for filling your tanks, as well as either an adapter for your reg or a second reg set so that you can rent Yoke tanks as needed then you should be fine.