I had Viking Citifix Single Speed/fixed wheel. I used it for about a year for commute to work and leisurely rides The bike looks cool, the paint job is nice, the white saddle was catchy. The handlebar is a bit too wide for my taste, the hoods are quite thin making riding on the hoods cumbersome.TThe whole handlebar was loose when I got the bike so I had to fix that. The caliper brakes were weak, so, I had to adjust them frequently. They were not reliable. The frame size was OK, and it put me in an aerodynamic position which was good. The gear inch ratio was good for a single sped 46T/16T at the expense of being slightly difficult at climbing, but it provided good acceleration. The wheels were 23 mm which provided good acceleration but, every other week I'd have a puncture. The back wheel got bent without trauma so I had to change it. The chain did not last long. The frame proved not to be as solid as I expected. Though it weighs somewhere between 13.5-15 Kg Overall, it served me, but I had to serve it a lot to survive. I guess the better single speed options would be, Specialised Langster, Charge Plug 0 or 1, Fuji Feather, Genesis Flyer, depending on your budget and availability of 2nd hand ones.