Cecilia, the pictured is a 15-90, I believe. I would get that one in a heartbeat if the price is less than $100. It's lovely and not that common. It appears to have a belted motor (15-90) not the potted one (15-91).
The 201K is as good as any 201, just modernized and more prevalent in UK.
The most obvious difference in 15 and 201 is the upper tension assembly. On the 15 it's on the nose plate. Also, the 201 has an integral light on the front of the machine, the 15's light is not integral to the machine. On the 201 the upper tension assembly is on the machine body facing the operator. The other big differences are not so obvious. The 15 is somewhat smaller and has a vertical bobbin assembly. The 201 is somewhat larger and has a drop-in bobbin. Each bobbin assembly, to me, has it's advantages.
Last edited by Vridar; 01-14-2014 at 09:04 AM.