I am an idiot and I accidentally busted my Sumiko Blupoint Evo iii. Anyhow, I was shopping for a new cartridge and an "expert" told me that MC cartridges were only necessary on older tables with heavier tone arms and that since my tone arm is made of carbon fiber I'd do just as well with a MM cartridge. He says they will both retrieve the same amount of info from the grooves of your record. Is this true? I've always been told that MC cartridges are the higher fidelity.
The current offerings of both types, and moving iron too, are such that it becomes more a matter of personal choice, taste and system compatibility, not necessarily in that order of priority.

So that wasn't very helpful was it?

About 12 years ago I switched from a nice Grado moving iron to a Benz Micro MC and immediately enjoyed what I perceived to be added "air" and inner detail that I felt, at the time, was afforded by the MC design. Since then I have stayed with MC by default, but a few friend's systems that use MM or MI and that I get to listen to regularly are also highly enjoyable.

An important part of this is consideration for the phono pre and other downstream components that will be used. After all, we listen to systems, not cartridges in isolation.
I adore Clearaudio Virtuoso Wood, but can't switch from Lyra Helikon since I know I'll be missing that unique MC precision and tone despite quite number of advantages and reasonable price.
This has been happening alot lately.
I've always been told that MC cartridges are the higher fidelity.

Only when your Phonostage is one of the better ones you can hear the advantage.
MM can make the life quite easy with real world Mid-Fi Systems, so don't worry. A lot of Users are very happy with those.
I moved from a ZYX R-100 to a Grado Sonata a while back. Although he ZYX had a nicely detailed sound, there wasn't enough meat on the bones for me. I've been happy with the slightly less detail and more warmth, especially with vocals. They both have strengths.
Your Sumiko Blupoint Evo III, is a high-output moving coil cartridge. That means you can run it into a moving magnet phono preamp. Regular moving coil cartridges are low-output. These need extra gain. If your phono preamp doesn't have the capability of running, or have enough gain for a low-output moving coil cartridge, a moving magnet may be the way to go, or another high-output moving coil. Check to see what your phono preamp/stage can run first.
I'm an idiot too so you dont want advise from me...