In my opinion, color is not a selling point. It can always get painted or paracord wrapped. Frame material trumps color any day. Some very important things are rack and fender mounts and other frame accessories, along with geometry (upright versus stretched out) and how each frame fits different components. I'm researching fat bikes for a future purchase and I'm probably going with Surly steel Moonlander simply for longevity of rack mounts and the frame being a "Swiss Army knife" and accepting of 5" tires. I'm also looking at the more aggressive Ice Cream Truck but the bottom bracket is turning me off.

Look at every attachment point, geometry, what you can and can't do with the frame, and consider your options. I would only go with aluminum if I was going to use frame/seat bags and wasn't planning on loading down a steel Moonlander with racks and fenders and 60+ lbs of weight, plus a trailer, plus some huge 4.8" - 5" tires. I wouldn't trust an aluminum bike holding all that weight with chromoly racks while heading to the river jumping down from the high water mark on a deer trail.

EDIT:
I probably still wouldn't consider aluminum or carbon fiber for a fat bike unless you're going bare or ultralight packing. That extra 1/2 lb doesn't matter, to me, over 30 lbs. Leave the ultralight to the speed demon XC racing on 1.8" tires.

Also, a big consideration is how fat do you want to go? -- 26 or 29er in 3.5"? -- or 26 in 4.8" or 5"?

I'm waiting for the day somebody mass produces a 29er frame that accepts mass produced 29er 5" wheels Ohhh yeahhh