LIMB - I just returned from the PB Conference in Dallas and was going to post some pics - but thought I'd respond to this thread first.
First- HABITAT is completely ineffective on duckweed and watermeal - based on my experiences.
Secondly- a SINGLE application of HABITAT is usually far more effective on primrose and gatorweed than two or three applications of glyphosate or 2,4-D (the later options often require repeated applications for acceptable levels of "root-kill" - although a single application of either product will cause "apparent death" through brownout.)
I would encourage a HABITAT treatment for those two perimeter plant species (and several others), unless you enjoy the act of repetitive treatments. Besides the time-savings, this 1-treatment aspect of Habitat actually makes its use cost-comparable to glyphosate.
If you go with Habitat, be sure to use a methylated seed oil (MSO) surfactant as directed by the label - or a MSO+Organosilicone surfactant.