My first really good eyepieces were orthos and the love stuck for many years and to some degree still does. A few years ago, I discovered the joy of wide-field observing with dobsonians, so I bought some GSO Superviews to test the waters. I was shocked by how sharp these were, for such cheap eyepieces! I bought three pairs, 20mm, 15mm and 10mm, for binoviewing, and when comparing the two 10mm's, I discovered that one of them was a little sharper and cleaner than the other. It was close to the equal of my 10mm Zeiss ortho, but with 70° AFOV and better eye relief. It was actually BETTER on faint deep-sky details, because it was much more comfortable in use.
Now this was fascinating, so I ordered some ES82 eyepieces, a 30mm, 18mm and 11mm, and shortly after I was able to find a used 8.8mm. A little after that, I received a 9mm ES100 as a gift (thanks Gene!). Naturally, I wanted to compare them to my orthos. Frankly, the image quality is shockingly good! In my long-focus Zeiss achromats and apochromats I can hardly see a difference at all, in terms of sharpness and contrast, between the ES82's and my orthos. The 18mm ES82 is actually sharper than my 18mm UO volcano-tops... And the 9mm ES100 is sharper than all my orthos, save for a 9mm prewar Zeiss and on par with a Japanese 0.965" multicoated Kokusai Kohki ortho. Using my 63mm Zeiss Telemator as a test scope, the 9mm ES100 showed the dim companion to Vega better than the 9mm UO Volcano-tops, on par with the Zeiss prewar ortho and only topped ever so slightly by the multicoated 9mm KK ortho. Lunar views in the 9mm ES100 with the 63mm Zeiss are simply incredibly good. The whole Moon is ortho-like sharp and the field is almost twice as wide as the whole Moon.
But for planetary observing, I almost never use single eyepieces any more. I use a Baader Maxbright binoviewer on a Baader/Zeiss T2 prism diagonal, perhaps a 1.25x, 1.7x or 2.6x Glass Path Corrector (think of it as a barlow) and two 25mm Zeiss OPMI eyepieces, a 1-2-1 König design. That adds up to a LOT of glass/air surfaces and yet, I see more than I ever did with a single eyepiece. The 25mm Zeiss OPMI eyepieces are the finest 25mm eyepieces I've ever seen, bar none.
But that doesn't mean I've never seen a ultra-simple eyepiece that beat anything else, even if my orthos and ES82's are virtually neck to neck. I once made an eyepiece, where the only optical elements was a simple achromatic doublet lens with 18mm focal length. It was housed in the barrel from an old 18mm plastic huygenian. Just a funny experiment, because I had read about astronomers using such eyepieces in the past.
This eyepiece was SHOCKINGLY sharp and contrasty! The AFOV was only around 12° - 15°, probably closer to 12°, but the views were unreal. Especially solar details were absolutely mindblowing, once you could get what you wanted to see, into the tiny field. This was a huge problem, so I never used it much. Once I got my binoviewer, it was game over for this eyepiece, since I didn't have two of them.
But I did use the binoviewer to directly compare it with my 18mm UO ortho. Funny enough, I could get them into focus at the same time and even look through both of them simultaneously! What I saw was completely shocking (again!) and jaw-dropping. This was a daytime test, and I was looking at a distant grain silo with some antennae on the top. Where the UO showed deep, black shadows, the achromat showed lots of faint details in the shadows. The difference was staggeringly obvious.
It has obviously occurred to me, that a Monocentric should be able to do the same thing, but they're pretty darn expensive, so I never got some. If I ever get the lathe, I've always wanted, I'll get some small achromats from Edmund Optics and build me some ultra special planetary eyepieces - and I'll make them in pairs, so I can use them in my binoviewer.