Hi, Considerations to keep in mind, which I haven't seen mentioned in this thread, or the other, is that it is said that all moving coil cartridges with an output of 1.5mv or higher generally act like a moving magnet cartridge in regards to loading, and generally work great at 47k ohm loading, so you won't have any problems to deal with there.
What I haven't seen mentioned, is that gain for your pre-amp typically will generally like, and be best compatible with a cartridge that will have about a 3.5mv output. (where most MM cartridges fall)
With let's say something like a Glider (which I think the new ones are at about 2.0mv, or 2.2mv?), you might find that you'll have to crank the volume control more than what you'd like, to achieve likeable volume levels from your system. I'm pretty sure your Mac Pre doesn't have provision for user adjustable gain settings. (I myself own a Mac MX-130 which doesn't)
This will be a slight incovenience due to mismatch, and then one must always remember to be careful switching inputs on the pre-amp, as switching over to FM, or CD could be so loud, that accidental damage could occur to speakers.
Other options would be a top of the line MM offereing from Shure, Grado, Audio Technica.
Your system (Mac Pre, and Amp) can certainly utilize better front end hardware than what I previously mention, but the bottom line will be "how deep are your pockets"?
You will reach a igher level of sonic nirvana with a med-low MC Cartridge, and external Phono Stage, and one can easily spend another $3-5K in this area to achieve this nirvana.
In my own VPI-Mac based system, I graduated from the nice, and relatively inexpensive McCormack Micro Phono Drive, which can be gotten around $300 used (Which another A-gon member now owns) and bought a Sutherland PHD Phono Stage, a $3K new unit which I paid $2k used from a-gon.
The upgrades were readily apparent, and should be.
I've been out of the mix lately with many of the new high output MC's out there, but make sure you do check their rated output for compatibility. Hope this helps, Mark