The only exception I can think of to Alchuck's comments would be if you are trying to get the longest possible cable run for a MIDI device - then, the parameter to look for in a MIDI cable would be the actual inter-electrode capacitance on the pair of wires that actually transmit the MIDI digital signals.
When transmitting digital signals, the lower the capacitance between conductors the longer the cable can be before the pulse edges are rounded off to the point of bit loss. At that time, you will get spurious results (errors)
I generally buy medium-priced cables that have REAL solderable connectors with metal shells, and only spend extra for really long (15-20 foot) cables because of the above-mentioned conditions.
I've not measured the capacitance of the Monster series (I too wasn't aware there WAS one) so I can't comment on whether they are any better in ANY way than the Hosa's (although MOST Hosa stuff I've checked out is pretty marginal)