I received my 15 rnd Baby Eagle mags from Magnum Research. First of all, the shipping was great! I ordered them 5 days ago (3 business days) and have already received them. Great to deal with these folks!
I'm pleased to say that so far I'm happy with my purchase. I took the mags out of their packaging and they fit perfectly into my CZ 75B. I ordered the steel based mags so there's a small gap vs the way that my factory polymer based mags look. Magnum Research also offers a polymer based 15 rnd mag so maybe this one has a better fit. But the gap doesn't bother me.
I haven't yet taken the mags to the range. However, I have cycled a magazine full of snapcaps and it fed and extracted everything flawlessly. The slide also locks back on an empty BE mag, as expected. So far so good. I'll be going to the range soon so I'll be sure to post a range report.
Here are some pics:
CZ 75B w/ CZ factory 10 round mag
CZ 75B w/ Magnum Research Baby Eagle 15 round mag (note the small gap)
CZ 75B slide locked back on BE mag
Both mags (BE on top, CZ on the bottom)