Which to keep! Pick one of these two soeakers

Why did you buy this "other" system in the first place?  I'm guessing it was for one of the pieces of electronics?  

So now presumably you have two complete systems.  If it were me I'd keep the best of the electronics and sell both pairs of speakers.  Even then that might bring you ~$3k.  Add $2k to that and go find a new speaker that you really like.

Having said that just keep them both...life's too short for such pondering.

BTW, I'm the worst at selling things (anything), I still have my first car, my first motorcycle, my first house, my first wife.  I also have three sets of amps (ARC, Pass, Hafler) to run three complete tri-amped systems.  Eleven amps in all.

Probably healthier to simply ignore my post.

Regards,

barts

@barts 

😊 do as I say, not as I do.

I agree with those suggesting optimization can be a big factor  You've had one for decades and they tend not to be too particular on set up  ESL's typically a different story   I would guess the Martin Logans have greater potential for realism, accuracy, esp for seated listening in the sweet spot  

Your opinions are super helpful, there are little bits of information mixed in to each that helps me piece together some of the greater experience you all have with these types of speakers. To those who are a little rubbed by me asking for the experience and opinion of others, I find it extremely helpful, and it helps me to bring attention to things I may not have otherwise consciously been able to consider in my decision. It also adds confirmation to the experience I've had, or helps me reconsider things that maybe I got wrong. There have been many useful points brought up here. 

I mainly bought this guys system for the VPI turntable, Audio Research pre-amp, CD Player and VT100 MKIII power amp. Those three items are nicer than the core of my #2 listening room that is also my home studio. There was a whole bunch of other stuff in the rig like a transient noise reducer, the Adcom amp, the speakers. I was initially thinking I'd sell the speakers but they turned out to be pretty nice which is what got me into the predicament of considering my Spendors for replacement. I wonder if I could fit both sets of speakers and wire them to an AB switch. They are different Ohms though, The ML are 4 ohms and the Spendors 8 ohms. I wonder if there is a way to wire them up to a couple of switches and turn off one, turning the other on. 

There was a Marchmand EQ and a Marchmand tube crossover also hooked up to this system that got sold out from under me. I would have really liked to have those to play with on this setup. That may have helped a lot with the Martin Logans. I feel they need a little high rolled off at times from what I'm hearing, maybe the lows bumped just a tad. Same with my Spendors, they are really bright but I really like the clarity 99.9% of the time. I have a sub that I use to fatten the room up. 

Is there a good EQ that I could invest in that ya'll would recommend? I really liked the Marchmand controls, it was 5 knobs and pretty simple and seemed well built.

i think the spendor s100 are of 1990 vintage, so not so old. since you have a sub i'd pick them over the martin logan, which look cool but didn't sound that great to me.