Well, you really have to go with where you feel most comfortable. There is nothing wrong with UK. Sometimes it's nice to not have fellows around, because you get to do everything yourself. On the downside, you have to do everything yourself, and you don't get the benefit of their teaching or insight. Not everyone who does NCC fellowship comes from somewhere with a dedicated NCCU. However, it is hard to know if you like it if you aren't exposed to it, and its obviously harder to do research without your own unit. You would want to use a lot of your elective time to travel around and work somewhere with an ICU, so you can get exposure and potentially build relationships with people in the field. This would help you match.
The fields of stroke and NCC used to be tightly linked, and many fellowships covered both. That is changing, and so not having a NCCU would not have as big an impact on stroke fellowships as NCC fellowships, although it might temper the kind of cases you get to see during residency.