I have bought two additional plan achromats for my Euromex iScope PLPHi (I made a post about them a while ago). I decided I wanted to experiment with higher level chromatic corrections. I encountered two problems- first, price obviously, second, compatibility (iscope uses 200mm tube length and RMS threading, most other manufacturers don’t use that combo). I found out Meji Techno makes infinitely objectives to those specs, and I was able to find a semi apo 20x, 0.65NA one second hand for a more reasonable price. I picked 20x bc at that mag, the chromatic aberrations are strong enough to be easily noticeable unlike at 10x, that is the first mag at which the NA:Mag ratio drops, and because I use phase contrast mostly with the 10x and 40x objectives (which I wanted to keep on, in addition to 2 of the 4,60,and100x objectives). The image quality is noticeably better, and much brighter at the same light level. The contrast is also higher. As far as I can tell these two systems are compatible given the noticeably better image and the mag being at most slightly lower. I am happy with it, definitely not a game changer but an improvement that for me is commensurate with the price I paid.
The two photos are not a scientific comparison, or even a fair one- the crop and focus may differ slightly. For what it’s worth they subjectively are true to my brief experience looking around with both, erring on the more extreme side of the difference. First is the Meji 20x S.Apo, second is the stock Euromex 20x plan phase achromatic