No first hand experience with either, from what I've seen elsewhere Nitron seem to get solid reviews, Hagon can be hit & miss.
Wilbers seem to be a favourite from the guys at Biker.ie (A fair few year round bikers there, their 5 year guarentee helps). There's a range for the 250, the one with seperately adjustable compression & rebound is above your budget
http://www.bits4motorbikes.co.uk/Wil...ml?listID=1781