In my experience, the Meps are easier to see in daylight as well as night compared to Trijicons. I haven't tried the Heinie sights. This experience obviously is dependent on my eyesight (slight cataracts and astigmatism).
I do have an affinity for my Meps. They've worked well in all my HK's. I also do like Heinies as well.
I too like my Mepros but have considered Heinie sights… Not yet sold on the straight eights.
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H&K, quality since 1949.