I can't speak for others but I can tell you why I sold mine.
A dozen years ago, had four of the 12-42 BR models. The older gold letter ones with the NP-R2 reticle. I upgraded those to the newer white letter with plain fine crosshair reticles because (1) where I shoot you have to be able to see your bullet holes and the hash marks just made that tougher and (2) at a range with a roof the gold numbers and hash marks are kind of hard to see. Sold three of them and bought three 2013 Competitions when they first came out. Reticles I didn't like but there were only two offered. The Competition models are lighter and with a 17 pound weight limit I can put more weight in the bottom of the buttstock where it helps. Others may disagree but I believe the glass is a little better in the Competition. There's also the psychological issue with the BR of having the hardware to illuminate the reticle which I paid for and have to look at but never once turned on.
Then the 2014 Competition came out and I could get zero stop, high speed turrets and fine crosshairs so the 2013's were sold and replaced with 2014's.
There were a couple March's mixed in also. A 10-60 and a fixed 40. Didn't care for either of those. The non-transferable warranty made them tougher to sell and I lost more $ on those two than all the Nightforces combined.
So I had a left over 12-42 BR. An excellent scope but if I'm ever in the position of NEEDING a fourth scope I'd go with another competition so it didn't make sense to keep it. I believe I paid $1250 for it so it cost me about $200 to own it for three or four years.
A used BR in very good shape is $1,000-$1,100 vs $1400 MSRP new. Used 2014 or later Competitions are pretty rare and command a high price, not all that much below what a new one goes for. I'd look at it with the assumption that it will get sold someday and how much will it cost to own it for a few years. My guess would be the cost of ownership of the BR isn't that much less than the Competition, but the initial investment is higher. Don't know about your bank but mine is paying me 0.013% interest on my Super Premium Double Platinum Interest checking account so I have no problem investing in scopes, etc.
The NXS is a great scope also but if you find one with a reticle you like, zero stop and 1/8" clicks the seller, if he knows what he's got, is probably gonna' want at least what he paid for it.
It's only money....