You can't judge fat bikes based on a wallgoose experience. I still have a cheap fat bike from bikes direct, but it's way ahead of a wally world special. It's a single speed (and I love my other SS, it's my favorite bike actually), and with a tire and tube change and some of my own components it's at about 31-32lbs (my scale isn't super accurate). The fat bike tires come out to a 29" OD, while my other SS is a 27.5" so comparatively I wouldn't say sluggish is the word, but it does take just a bit more effort to get it up to speed. BUT, since fat bikes run super low pressures (I run 12F and 10R psi) they really cushion the ride big time on a rigid frame, and they roll over everything in their path. It's like running a stock toyota on 31x10.50s at 30psi, compared to a lifted & locked yota on 33s at 10psi. It may not be everyone's cup of tea, but I personally love my fat bike like a fat kid loves cake. It's just stupid fun, everywhere I ride it. That being said, you really have to find your "happy" psi range, or the fat tires have some odd traits, like self steer. With the smaller 3.5" tire, I would think it wouldn't be as big of an issue however, but I don't know, as I run 4" tires. Hope this helps some.