synflex, flexicose, and a couple others have the fairly valid case to make
of easier absorption, and possibly greater availability as a result.

unfortunately, i am not aware of any documented large studies that prove
this out with replicable results. but it stands to reason that it might be
the case.

some have found that the pill forms upset their stomachs while the liquid
does not - yet others find both do - go figure, for each to find out for
themselves.

the variations between brands boils down to whatever other 'special'
ingredients the manufacturer might add in - of benefit? - once again, no
verifiable studies that i know of. (haven't looked in a while though)

in any case - as with the pill forms - those with shellfish sensitivity and
such should not partake. and of course, the liquid version is pricier...

be well

paul