I used to want this knife til I researched it. What I found was hit or miss. Some people say it's built like a tank. Other people say the liner lockbar is so thin that it gives out very easily. The NSN number doesn't mean much. Having talked to people that have served, they say a lot of NSN stocked items are rubbish. All that means is that the gov't basically got conned into paying for a large quantity of a given product, which doesn't necessarily mean that product is good. I'm not saying everything that has an NSN number is bad, and I certainly don't want to toot the DDR/HTM horn, but they do have knives which were granted NSN. That was just an example of the extreme ends of the scale. To that end, you might want to do a bit more research regarding that XM-1.
Regarding handle thickness, sometimes I feel like the Incredible Hulk because I prefer thick handles, and I don't even have that big hands. I have longer fingers, yea, but not giant palms. I just don't understand how slim handles can feel comfortable. Stuff that's like 1/4 to 1/2 inch thick just feels like it can wiggle around in my hand. Granted, there are exceptions if the designer puts finger grooves in the right area to help with gripping, but I find few designers that can pull this off. Even on my firearms with interchangeable backstraps, I use the large ones. Friends pick it up and go, "How the heck do you hold this thing?" I just shrug and pick it up.
I guess I'm one of those people where a Dr. Grip pen feels like I'm writing while holding a toothpick.