IME, horst bikes pedal pretty darned well, not as great as many bikes with SPV shocks, but then they are more sensitive and have better suspension usually than bikes with SPV shocks, then you get SPV+horst link and you can do a lot and tune it a lot of different ways.
The big negative with a horst link is the stiffness of the rear end. It's difficult to do, you need some kind of angular contact bearing, needle bearing, bushing, or double-bearing to impart stiffness to the rear end, as well as beefy linkage and chainstsays, these things drive up cost and are hard to design into the bike to function well.
As opposed to nearly everything else, the member that the rear wheel is attached to is not directly connected to the main frame. On other bikes, the wheel is usually on the swingarm, which directly connects to the frame. This doesn't inherently mean that a single-pivot bike is stiffer, BUT, there are special considerations that have to be taken into account to make a horst-link bike "stiff", and it adds weight to the bike.
I think the real trend these days is to design a solid-rear-end linkge type bike that is progressive and has a pivot that is active and pedals "decently", and then make up the difference with a romic or 5th type of shock. The turner and ventana definitely take this train of thought IMO, as well as the specialized demo9 which seems to address shock-sideloading by attaching it to a member that is directly connected to the frame. The bikes like the turner and a few others seem to give the best tradeoff...of course there's the issue of the brake, but not all horst link bikes are completely stable under braking anyway, at least according to braketherapy they aren't perfect. I think the real advantage of horst link bikes IS the active braking, but depending on the person and the application, it may not be a big issue.
The big negative with a horst link is the stiffness of the rear end. It's difficult to do, you need some kind of angular contact bearing, needle bearing, bushing, or double-bearing to impart stiffness to the rear end, as well as beefy linkage and chainstsays, these things drive up cost and are hard to design into the bike to function well.
As opposed to nearly everything else, the member that the rear wheel is attached to is not directly connected to the main frame. On other bikes, the wheel is usually on the swingarm, which directly connects to the frame. This doesn't inherently mean that a single-pivot bike is stiffer, BUT, there are special considerations that have to be taken into account to make a horst-link bike "stiff", and it adds weight to the bike.
I think the real trend these days is to design a solid-rear-end linkge type bike that is progressive and has a pivot that is active and pedals "decently", and then make up the difference with a romic or 5th type of shock. The turner and ventana definitely take this train of thought IMO, as well as the specialized demo9 which seems to address shock-sideloading by attaching it to a member that is directly connected to the frame. The bikes like the turner and a few others seem to give the best tradeoff...of course there's the issue of the brake, but not all horst link bikes are completely stable under braking anyway, at least according to braketherapy they aren't perfect. I think the real advantage of horst link bikes IS the active braking, but depending on the person and the application, it may not be a big issue.