I think this brings up a more fundamental question of what exactly should a reviewer's system be capable of doing and should it be geared towards revealing meaningful differences between components.
If you think back to the late 80s throughout the 90s, a large % of reviewers had speakers from the likes of Apogee, Magnepan, Infinity/Genesis, Acoustat and Soundlab. The reason being, at least for that time and to my ears today as well, that these speakers made it relatively easy to hear differences between gear. When I did my big preamp shootout more than 10 years ago, my Acoustat Spectra 2200s made hearing what each piece of gear did in the system trivial...same for cable swaps. I am the first to admit that amps are more challenging because the load is not always amp friendly (I had some OTLs that oscillated badly due to the load reactance) but for preamps, cables and sources it made reviewing easy.
Many of those companies went out of business or fashion and now reviewers are using whatever they think "sounds good". What most people don't realize is that the later Apogees were easy loads for all amplifiers that could handle 4 ohms. Magnepan too. Apogees also measure well, as do Acoustats and presumably Soundlabs. They have quite linear responses with no big peaks or suckouts. My Acoustats were within 2db from 200Hz to 15Khz (then they rolled off gently). In the bass I handled room mode peaks (you can't fill in the dips) with a digital eq (digital in and out). I got linear response and coherent sound, which allows you to hear things you miss on other systems, like how gear is handling sense of space and phase relationships, which can have big impact on overall SQ.
If I read a review from someone who had Apogees or Soundlabs as speakers I tend to take the review more seriously because I know how well you can hear things with these types of speakers. Someone reviewing on a pair of Harbeths...well... If they have horns I still have to think a bit about what I know of that speakers potential weakness and strengths. They are not as linear as the best planar speakers. They will be better for assessing dynamics but perhaps not tonality and timbre or perhaps micro dynamics (I still find stats the best for evaluating the subtleties of music).
One thing I think is critical is to avoid multi-way, high order crossover speakers that are using multiple driver material technologies. This will smear timing, tonality and dynamics...something you notice compared to live and to systems with a different concept.
I am assuming that Jeff can have only one system and therefore I think as reviewing is a profession for him he should consider, as a professional, what tools allow him to do the job of reviewing gear the best and not what the public would consider "conventional". Tools of the pro need to be considered more for a specific purpose rather than just general listening pleasure (of course they should allow this too but not cover up flaws). That is the major flaw I see in Jeff's candidate list is that these are not speakers that will allow the pro reviewer to be at his best...it will be harder work. Sure, once you get very familiar with a system you can learn to hear around it's flaws and to still hear differences but when those flaws are minimized it makes life a lot easier.
If I go back to reviewing again (for the third time) I would likely have a pair of planars specifically for that purpose. Maybe something like the Acoustat X with built-in OTL amps and then just review everything except amps.
Finally, quite a few reviewers out there have turned to Audio Note speakers. In one way this is baffling because in some ways they are quite colored but in another it is understandable because 1) They are simple and don't get all messed up by crossovers 2) they are reasonably sensitive and have a pretty widebandwidth (if placed near the corners) and an easy load...so flexible and 3) You can differentiate between components with them pretty readily (the colorations they have don't seem to gum up the resolution works too badly). IMO, they are too flawed overall but I can see why they attract people.
It is interesting to note that Art Dudley has taken the multiple speaker approach (or at least he used to). He had AN speakers, Quads and some Altecs oh and I think he had Orangutans as well. Maybe now he is only with the old Altecs as he has become a bit of an anachrophile (after hearing some old designs I can see why though).
