I have an Ampex MM-1000.
All of my 1" and 2" tape is on precision reels...think that's all you could get in 2"...
Anyway, I've experienced the difference between the standard and the precision reels with 1/2" on the Tascam 48 and 58 machines I used to have and now I'm dealing with ugly tape pack issues on my 1/4" BR-20T. What I find with the precision reels is that the ID of the hub is tighter so there is less eccentricity between the reel and the reel table, and the flanges are less prone to being warped or bent, and furthermore the manner in which the flanges mount to the hub is more precise so there's less chance of a flange being wonky. What does it all mean in the reel world? heheh...
On the 1/2" machines I was sold on using them because there was less tension arm oscillation...the tension system just had to work a whole lot less when using the precision reels. Now, I understand that the whole purpose of the servo tensioning system is to deal with that stuff, but it can only react so quickly and unless you are working with a closed-loop system those oscillations are going to be present in SOME fashion inside the headblock...and secondly the tape packs were like glass with the precision reels.
I haven't yet used a precision reel on my BR-20T, but the thicker plastic 7" reel packs tape beautifully and the standard three-screw 10.5" reel packs something ugly, and its not tape tension either. I've measured all that. With the 3-screw 10.5" reel the tension arms are hopping around and I can try and try to to center the reel on the table but the reels themselves are not well balanced so even in library wind you can feel the machine shaking and the tension arm is shaking...7" plastic reel on the trident mount? It nicely centered and everything runs so much more smoothly and the tape packs just beautifully. Same experience I had on the 1/2" machines so that's why I'm looking for 1/4" precision reels and why I like 'em. Everything else works you know? But my experience is that the precision reels work better, at least with the machines I've had.