Never picked up the 8x.
Still really like the 12x. 10x FOV with a little extra magnification. 10x is fine but I always wanted a little more. I probably would not go 14x over my 12x. I have never used a 14x so keep that in mind. At some point handholding has to be an issue. FOV takes a hit as well.
I think out West 8x, 10x, 12x, 14x, can only go so far. If looking for a solid buck I think having a spotting scope is helpful especially when it's hard to get close in open country.
Also depends if I'm solo OR my son with me? Son and I, I take the 12x and he take the spotter. Worked great last season. Glassed up a dandy buck, couldn't see enough detail with 12x, spotter confirmed solid buck so we bailed out of the drainage, and he harvested the buck the next morning. So far it's his BOL.
If it's just me I might be able to make an argument for just the 14x. I don't know how much more detail I can pick up 12x vs 14x. >>> Same season I glassed up a nice buck, I was solo, closest I could get was 350 yards maybe a little more. I couldn't pick out enough detail. A spotter would have confirmed if this buck had what I was looking for. I ultimately passed. With the 12x I was really on the fence. I had my crosshair on this bedded buck for 30 minutes. Could not make out brow tines well enough (I love brow tines on a mature buck FYI), mass was questionable with a 12x, etc. I still think about that buck, with the data I had, I still think the decision to pass was good.