I'm disagreeing with Zanx. Have had a Hagon monoshock on my bike for over 5 years, must have done over 80-100k in that time. It's been rebuilt once. Handling is absolutely fine, the bros is a decent handling bike, a pogo stick would show itself awfully quickly. Build quality is brilliant, it's durable and cheap. I would absolutely recommend it (on a Bros and on the road anyway, I'm not going to pretend I've tested one all makes of bikes on the track or anything).
It's not awfully adjustable, rather basic - but then I'm not one that spends forever tweaking.
About 250 quid? - still must be 150 quid cheaper than Maxton or Technoflex.
That said, if it was going on a spendy sports bike I'd prolly go for the bespoke option - horses for courses.
My 2p.