That is an interesting comparison for the number of EP's tested, but he left out the Siebert Star Splitter, which is one of the best planetary eyepieces out there, and quite possibly the best planetary eyepiece for the money. Anybody interested in an EP in the 6mm range might do well to read what follows from my personal experience.
I have a 6.4mm Star Splitter. It works GREAT in any of my scopes from an f/4 Newtonian to an f/15 Mak-Cass. It is very light, it has consistent eye relief across the range (like the Radian series, but not quite as much eye relief, which is actually a good thing for high mag views), it has a consistent eye lens across the range (and it's as big as a 12.5mm Ultima eye lens), it holds a heater strap very well and transfers the heat better (unlike my TMB 9mm), it is tack sharp to the edge of field, from 2.9mm to 7.9mm the Star Splitters come in 0.5mm focal length increments. Nobody else does that to my knowledge, and that may be important in fast focal ratio scopes, and there is also 8.9mm and a 9.9mm 3-element variant without the front diverging doublet cell. Those are awesome on long focal ratio scopes.
I know that Harry Siebert has a very small production compared to most of those other EP's being reviewed, but I think the few of us who have bought one or more of his Star Splitters have been seriously impressed with the high mag images they throw up. They retired my shortest Celestron Ultimas + Ultima 3-element barlow combination for high mag viewing in most of my scopes (the 4.4mm and 6.4mm Star Splitters are only usable in my f/15 150mm Mak-Cass under the best seeing conditions due to the insane mags they produce in that scope....nothing to do with the image quality they can achieve).
FWIW, if you have a 12.5mm Ultima, then that size eye lens and eye relief are about the same as the Siebert Star Splitters. If a person likes squinting through some of those 6mm EP's with peephole eye lens, then more power to them. I'll keep my Star Splitters. To have tested so many EP's without including the Star Splitters, especially considering their increasing reputation among owners, seems a bit odd to me.
Harry does not usualy anodize his EP's black and they are not polished to a mirror smooth finish, so that may scare off some potential buyers. I will say this about their build quality: none of my six Star Splitters have ever developed a loose, rattling element or had parts loosen up, unlike some of my more expensive and better known EP's. About 50% of my other EP's have had some kind of loosening issue at some time.
I would also say that my overall reaction to the Star Splitters relative to similar focal length EP's has not been subtle as well.
Anybody into binoviewing should consider the Star Splitters as they are so lightweight and because two of them will weigh about what a Radian does....and you will get change back from what a single Radian would cost you in most cases. A Burgess TMB looks more like a Radian, but as a TMB owner I can tell you that the Star Splitter performs more like a Radian. If you had a 12.5mm Ultima that worked well at f/4 and weighed a lot less, then you would have about the same as a Star Splitter, but at a longer focal length. The main drawback to the Star Splitter series is their lack of longer focal lengths, but their main strength is they are very comfortable EP's in short focal lengths where other EP's run into trouble whether it be weight, cost, short eye relief or peephole eye lenses....or a combination of those drawbacks.
I have a few other Siebert EP's, but the Star Splitters are my favorites compared to other brands. Maybe the fact that you order your Star Splitters and have to wait a few weeks for them to arrive also turns some people off, but the guy who built it will also fix it for you, much like Tele-Vue does. You also have a trial period to send it back and get a full refund if you don't like it. Since they are so light, I suspect a fall has less chance of doing any serious damage anyway.