I have not directly compared the NL Pure 8x42 to the 12x42 but I own the 12's as well as an older pair of 10x42 SLC's (and a fewer other optics). This is a topic I have thought about a lot because I'd love to have a pair of 8x42's but my CFO, er lovely bride, doesn't see it the way I do. LOL.
First quick answer to your question- Yes, both.
My experience might help - not exactly your situation but here goes:
I really like optics and I am fairly perceptive to the differences between them. If I was starting over from zero, and I had no Bino's, but knew what I know now, I'd probably just get a pair of 10X NL Pure and call it good. But that is because I don't carry glass when archery elk hunting and my primary use is open country scouting and hunting. This also assumes that you'll have a decent spotting scope with you if you are hunting in conditions that support a 12x binocular and the same applies if you are carrying 10x bino's.
Put another way, I think it is a bigger relative handicap to use the 12x in closer cover or when handheld than the handicap of using the 10's in open country. The 10's are very useable in open country. I've done it for over 20 years. The 12's are better for sure, especially off a tripod, but the 10's are fine when complemented with a spotting scope. However, once you get into tighter cover or need to glass for longer periods of time without a tripod, or want to glass from a standing position - then I think the handicap of the 12's is significant.
Long winded way of saying that the 10's are a good middle ground. And I wouldn't want to own just a pair of 12's.
I say the above having owned a pair of SLC 10x42 for over 20 years, and more recently a pair of 12X NL pure's for two hunting seasons. If I only had the 12's I would definitely get a pair of 8X NL Pures to complement the 12's. But I haven't actually used the 8's yet, so I'm saying this based on my experience with 10's, 12's and various other optics. And my kind of usage.
Longer discussion for perspective.
I have a well loved pair of 10X42 SLC's and a pair of 12X42 NL Pure. Before the Swaro 10x42 I had a pair of porro prism 10x50 Swaro's that were absolutely amazing handheld. Swaro gave me the 10x42 SLC as warranty replacement for the 10x50's and said that the optics were better. I never compared the 10x50 side to side with the 10x42, but I always felt like the 10x50's were quite a bit better than the SLC 10x42 in actual field use when hand held. Point being there are a lot of factors at play when comparing a viewing experience.
I bought the 12x42 Pure's specifically with Western Deer hunting and tripod use in mind and I selected them in competition against the Swaro 15x56. I landed on the 12's partly because they should excel on a tripod while being somewhat useful handheld from a sturdy seated position while being smaller and lighter than the 15's. If Swaro came out with 15x56 NL Pures, then I might think about selling the 12's and going with the 15's.
I consulted a number of very experienced hunters (think Coues deer and such) and read / watched an enormous quantity of reviews before buying the 12x42 NL Pure. The consensus seemed to be that the 12x42 NL Pure were a reasonable substitute for the Swaro 15x56, offering very similar practical resolution in a smaller and lighter package while still being "okay" to use handheld. You didn't ask that question, but I saw the comparison come up in the replies.
That is how I landed on the 12 NL Pure.
In my case I already had a decent pair of 10's and I specifically wanted something for tripod use for open country mule deer and I did not want to give up much to the legendary Swaro 15x56 on a tripod.
By now, I've carried the 12 Pure's a bit in the mountains and my feeling is that compared to my SLC 10x42, I have significantly more difficulty using the 12's handheld (even with the forehead rest) and find myself wishing I had my SLC 10x42 when handholding. Like, it just isn't "fun" with the 12's handheld but I can do it from a solid locked in seated position.
Lately I mostly archery elk hunt and we almost never carry glass when doing that. I bought the 12x NL Pure's for scouting and future mule deer hunts. However, I am seriously considering a pair of 8x42 pures for Archery elk, general backpacking and so on because they would be so useful when handheld. Probably even from a standing position in the timber. One of the reasons I'm considering it is due to the phenomenal field of view. That, and I expect the 8x42 would be quite bright and just plain a lot of "fun" to use. But I would still keep my 12x NL Pures for their dedicated primary purpose.
If I didn't already own a good pair of binoculars (such as my SLC 10x42) and if I could only have one pair I'd get the 10 NL Pure's and be done with it.
In the end I may end up getting a pair of 8's to complement the 12's, with the hope that the 8's would be functional for casual use, "quick" looks while standing and for use in thicker country. I would not carry both at the same time, but would use the 8x when the activity and terrain encourages their use. Elk are a lot easier to spot than Mule Deer.
I keep the 30 year old pair of SLC 10's for my adult "boys" and friends.
