Why a low output M.C. rather than a high output?

Since many cartridge manufacturers make both High and Low output models why would someone prefer the low output which very well could require a step up transformer along with another set of cables? Wouldn't resolution be less this way with the extra step?
Fewer turns on the coil mean it is lighter. The whole stylus assembly is therefore lighter and hence more responsive.

You don't need a step up transformer if you have a preamp with sufficient gain in the phono stage. Better sound that way, too.

audiophile logic is 'no logic'. follow your pre audiophile instincts for logic.
More turns means that it is harder to manufacture and more prone to breakage. MOST of the top cartridges are low output. I would have agreed with Metralla until I got a step up from Bob's Devices. My phono stage has plenty of gain but the step up makes a LARGE improvement. See also recent discussions in Stereophile about transformers. Many of the top phono stages have them built in.
Wiki sais more than you need to know...
The high output MC's I've seen have an output of around 1.6mV.Alot of phono pre's like to see at least 2.5mV which puts the high output MC's in a less than prefered range.You will need a preamp thats up to the task of providing enough gain.