I am looking to have a fun gun that will reliably shoot to 700 yards.
If you are only shooting to 700 yards, and your target is deer, there are a BUNCH of standard cartridges that will do that accurately, with ease, without going to a boutique round like the 26 nosler.
Heck a .260 (or any of the various cartridges that are very close in concept) would work very easily for deer.
In a short action, standard .270, 7mm, and 300 WSMs would all work, as would any of the similar long action cartridges.
If you want to be good, it takes practice, which costs money. Generally speaking, the more you practice, the more you improve your skill set, so lets look at costs.
26 Nosler brass ($66 for 25 rounds at Midway USA) is absolutely retardedly expensive for what it is.
That is $264 for 100 rounds of brass.At the same store you could get 100 rounds of 7 Rem mag brass for $73.
Personally, I would rather be able to practice a bunch with a 7 rem mag, versus very little (with equal amounts of $$ spent) with a 26 nosler, when it came time to make a critical shot. You simply cannot buy a skill set.
If the 26 nosler had brass available at a similar price as 300 win and 7 mag brass, then it might be worth it, but at the grossly inflated price that they charge for the boutique cartridge, I could not recommend it to anybody.
Either way you are dialing for the shot, and there just is not enough of a difference to justify it (to me).
In short,from my perspective, the juice is not worth the squeeze.
Others may feel entirely different.