I saw that at prototype level and found it curious. Of course the crop factor of m4/3 gives it an edge over larger sensor formats so the MP-E65 doesn't reach 1 micron/pixel levels without a bit of extra help.
I like the LED lights as at that magnification, the "light loss" is simply massive. I wonder if the aperture values reported are the effective or physical values? Basically that's the difference being diffraction limited, and stupidly diffraction limited. For comparison, the MP-E65 goes from f/2.8-16 physical, for a range of about f/17-96 effective at 5x magnification. The non-existent depth of field doesn't help much either.
Also the comparison prices they list are out, although given the article was written a quarter ago things can change. Typical street price of the MP-E65 is in mid £800's, and as far as my memory goes, has not been anywhere near the £1250 they mention in the last few years or so. I got mine for £600 new before the world economy fell apart. The PanaLeica 45mm is now £550 minimum but Amazon and Jessops seem to indicate a conflicting cashback system going on which may further reduce that a bit. I see that lens as different usage anyway.
If I were solely committed to either of the supported mirrorless cameras then this would certainly be an interesting tool to have around. It is rather niche so unless you specialise in that niche, the uses might be few and far between like I find with the MP-E65.
At a practical level, if you already have a 1:1 macro lens, you can often easily modify that for more magnification anyway. Not to 5x, but up to 3x isn't too difficult. Just use some extension tubes and/or a teleconverter.
_________________Canon DSLRs: 7D2, 7D1, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 85/1.8, 135/2+SF, 70-300L, 100-400L, 100L, MP-E 65, EF-S 10-18, 15-85
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 50/1.4A, 150 macro, 120-300 f/2.8 OS
Compacts: Sony HX9V, Fuji X100.