For me Mecgar was a really big miss. The one I had and tried fed 2 rounds out of 5. After the first 2 rounds the rest of them were down in the middle of the magazine. The ACT mags have worked great for me. I will probably change the base though, I'm not that big a fan of the huge base they have.
I have not had a good experience with either Tripp or Mecgar 10mm mags although both are OK with 6 or 7 rounds only...the Tripp Research Cobra is supposed to be a 9 round mag and sometimes one can beat 8 into them.