Have you ever used a separate speaker selector unit to audition speakers? Would you?

DON’T WASTE YOUR MONEY. I tried it and this is what I learned.
I have a Bryston box and as those things go it’s as good as any but... they all are an abomination. After spending ridiculous amount of money on cabling, you are going to introduce one of these absolute sonic weak links into the signal path?
Why would you want to run your signal through one of those and make a judgement call when you wouldn’t want to run your signal through it all the time?
Besides, there is no way to make meaningful judgements A/B ing speakers. You have to listen for extended periods.
Take two minutes and swap the cables. Your ears will thank you and you’ll save money to boot. My .02

@rrcpa I'm convinced. 

Since BOTH speakers go through the unit, a comparison would still be valid.

@aburn Well, that is one key point of contention, and you can see I've pointed to it a couple times in previous posts. You can also see different arguments for and against the usefulness of the proposal. Rather than rehash that material, I would just suggest reading the thread from the beginning.

For those of you with a myriad of arguments against using a GOOD speaker selector I say great, don't use one. I find it almost essential for making A/B comparisons. No, there is no free lunch so you have to do some work, like figuring out how to level match each and every pair of speakers.

I don't think I or anyone ever said that a speaker selector was the ONLY method that should be used. Every audio component requires a long-term test. But, audio memory being what it is (generally poor, despite what you may believe) this is the only way to hear glaring changes in their raw state. Is that valid? Sure, as one data point.

Are selector switches a weak link? Maybe, but I don't think that a GOOD selector box color the sound. At least I, my former customers and distributors never mentioned it if they did. But as @ aburnhamuu45 mentioned above if both speakers are wired through the same selector what's the difference? You are evaluating the delta between two equalized sources. Your long term test (without the selector) will provide your sound baseline evaluation.