My wife shot a K100 mk 7 this weekend and wants one (or a P1, maybe mk7, maybe mk12) to replace her G19 because she felt that it was more controllable and easier to shoot for her.
I've done a fair bit of reading on these, and I'm not seeing many negatives other than price of magazines and availability of holsters.
Still not thrilled with what seems to be a pistol with little track record, but she seems determined.
Anyone familiar with any reliability issues with these pistols?

I am.

they need cleaned a lot.  like every 300 rounds.

Be sure you buy an MK12 version to avoid the frame cracking potential (triggerguard) of the MK7 series.  The P1 is nearly identical in size to a G19 if that is what she desires.  The P11 is not my thing, don't like it.  I like the K100 size personally.  They are dead reliable.  Use a good grease on the rotation face on the barrel and the crosspin in the frame

The MK7 series isn't made anymore although there are still guns out there.

which is why I told him to be sure and get an MK12 version

I bought a MK7 NIB about a month ago for $329 online. As for the trigger guard breaking there are replacement spares available online pretty cheap .  Spare mags are $50 each but CZ75 mags can be converted. The notch needs to be added to the front of the CZ mags.

This is very true, my P11 needs a deep clean every few hundred rounds in order to function correctly. They do not run well dry or dirty.