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They had excellent polish, but due to the older coatings, didn't transmit the percentage of modern eyepieces. Plus, the original Plossl design (which they may not have followed--some talk is that they followed the 1938 re-design by Konig) wasn't well-corrected in the outer field on today's short focal ratio scopes.
I had a set and loved them in my f/15 refractor, but I sold them and replaced them with TeleVue Plossls because the TeleVue's were better corrected in the outer part of the field.
As my tastes evolved, I actually ended up replacing the TeleVues with the 5-element Meade Series 4000 Japanese-made (by Kowa) "pseudo-Masuyama" design "Super Plossls" in the late '80s because they were equally well corrected in the outer field but did not suffer the vignetting common to the TeleVue Plossl design. They weren't really Plossls, of course.
Good Plossls have an incredibly small spot size on-axis, and are exceedingly sharp. It is the outer field, I feel, that distinguishes one from another. Looked at from that standpoint, unless you have a long focal ratio, you're better off with more modern offerings.
The Takahashi LE, which you mention, is also a 5-element "pseudo-Masuyama" design and not really a Plossl. It's a good eyepiece above f/5 to f/6.
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