Speaker companies with a focus on parts quality and measurements

Personal bias, but Reference 3A are beautifully matched in terms of price to performance. As are Acoustic Zen Adagios.

You should watch R Vandersteen U-Tube video on pistonic motion.....real science about how driver cones behave ... or not.
He has been working on time and phase accuracy for decades, which some have just discovered...

Researching my next upgrade and am looking for good price/performance ratio with high quality drivers and public measurements.

You may want to have a look at Golden Ear .

+1 for Vandersteen speakers.
The Shahanian's are nice speakers, and I am glad they still have a following, but they rely on reflected sound, much like Bose. A nice sound presentation, but not very accurate, in my opinion.
Once you go 'phase aligned', you won't go back...

Appreciate all the suggestions guys. I should have specified a budget though, as some of these are just too expensive right now. Probably looking to spend $1000 to 1500 on a pair of bookshelves, possibly up to $2k. Some of this stuff, especially the zen adagio junior, looks great but I'd have to find a great used price.

I've owned pair of magnepan 1.7 before, but they didn't really work due to my small room size. The planar sound is something I really enjoy in both speakers and headphones, which is why I'm drawn to speakers that employ those type of drivers.

The Revel M106 for $1600 would be an option, as would the Zu Omen or PSA MT-110. I've got a lot of review reading to do.