I'm a big fan of the mid-length, so I've owned a few...
Armalite - Nice because they are a medium-light profile from the get-go and chrome lined, and for a very reasonable price.
RRA - The HBAR (that's FULL HBAR, as in .920 all the way to the gas block!) is ridiculous in a chrome moly barrel. I owned two of them. One from ADCO with the additional $50 government profile job, and one from Pete in NH that I sent to KKF for a "turn and flute". I was much happier with the balance of them after the weight loss. Trust me, that thing is FAT. It weighs more than a comparable Bushmaster HBAR because there is no step-down before the gas block like most companies. Once I had them profiled, I was very satisfied with them. But back then, I had NO other options, so spending $289 was the only way to get a mid-length. There are less expensive options for sure.
CMMG - I replaced my last RRA mid-length barrel with a 14.5" mid from CMMG. I put it together myself, and just got it back from www.ar15barrels.com having the flash suppressor permanently attached. The balance is AWESOME, and it feels lighter than my 16" Bushmaster superlight. It's not, but the balance makes it feel that way. With a DD 9.0 and standard FSB on it, it really looks like an SBR since there's only 2.5" of barrel out past the front sight.
I also just put together a build using a Denny's guns Recon barrel, and that thing is a LASER!
I have no experience with Sabre or Bravo Company, but I wouldn't hesitate to give them a shot if I were in the market for another mid-length.
No offense to RRA, because I like and use their uppers and lowers and parts, but I think their HBAR+ barrels (stainless excluded) are a weak spot for them.