As I have been lucky enough to switch between my fat bike and hard tail I have begun to ponder all the things I did and didn't realize for better or worse about my other tool in my tool belt this winter. To be bluntly honest, I have either run or biked almost every day this winter in Colorado...so I really can't complain. This includes the days of twelve inches of powder, days of 1/2 inch thick ice, and days of 60-70 degree balmy weather with patchy dry trails. I can give the fat bike this, it is a versatile ride. The funny part is, it is such a slow going machine, I don't need miles of dry trails to keep me entertained. I can usually entertain myself in my ten mile local trail system given the degree of climbing that we have.
However; where the fat bike is a jack of all trails...it can be a master of none based upon your equipment and the conditions. Take my set-up, super wide beefy 4.5 inch snow tires with aggressive treads. I don't think there is a better tread for riding unpacked single track powder in the front range. This set up even did pretty well after a recent ice storm that I felt better riding my bike to and from work instead of driving my car.
However, even on packed groomers there are better options for riding in the snow based upon the type of snow. You can pick a narrower tread or a tread with less rolling resistance based upon how hard packed the snow is. The temperature of the snow even comes into factor since a warmer snow temperature will mean the snow is softer and will sink in deeper. Circuit races run in warm or unpacked conditions usually turn into tripod races pretty fast since running with a snow bike in deep snow is pretty ridiculous in of itself.
The tire options are mind boggling and compare to cyclocross in ways I never expected. Not only can you pick different rims but also different tread patterns, tire widths, and psi. More options than a UCI cyclocross racer knows what to do with and even with a tubeless setup are comparable to prices for tubular tires. I know it seems like I am really emphasizing the tires but honestly the tires and wheels are the most important part of your set-up.
On hardpack, the performance of the fat bike is even more dependent on the tire and rim set up. Even though a super wide tire may be pretty comfortable on a rocky trail or long ride, you may pay for it in the increased rolling resistance and weight. Another thing I have noticed is how squirrelly the set up can be in technical switchbacks and tight single track. When those tires getting rolling they really don't want to stop! However, I can pull off several hours of riding trails that would normally aggravate my carpal tunnel or low back on my 100mm hardtail but do just fine on the fat bike.
In summary, the fat bike is a pretty versatile ride. If you are looking for something to tool around on in your local trail system in all four seasons you probably won't be disappointed. Who knows, maybe it will get you to the grocery store or even work one day when your car can't make it out of the driveway. Mine certainly has.