only ever had a Hagon one on mine as that was what previous owner fitted not long before selling the bike, it did need to be sent off to have the damping serviced (poss. air in it) but Hagon fixed it promptly with no fuss under guarantee. After that was fine, damping is adjusted with a single screw taking care of both rebound and compression and preload with fairly standard castellated adjuster ring. Hagon were good on the phone too with regard to setting up correctly, although new ones are set to right kind of level as sold. Last time I looked they were £250 or a bit more.
Obviously doesn't have that Solo/pillion/luggage quick adjust preload but most riders I've spoken to on standard shocks have usually run on the higher preload most of the time.
not many shocks around cheaper, think there's a hagon with no damping adjuster or a betor or similar available. More expensive ones with more adjustments are Maxtons tailormade to suit you option or WP or Ohlins or maybe Nitron, maybe Technoflex (Dutch)
There is a slight compromise on the rear suspension due to no linkages but without the sophistication of the WP shocks fitted to KTM off roaders which also had no links, and CCM had a linkless setup but inclined further to get the right suspension action.
All the above was neccessary I believe to squeeze the standard exhaust in and keep noise down. Only problem I found was riding quickly over large bumps and rises when you tended to get pitched up from the seat a little more than some bikes, otherwise suspension soaks up bumpy roads well.
Think any secondhand shock in a breakers may be on it's last legs. Hope this helps and not too much info!!