My experience of Vortek kits is that they are high quality, particularly the seals. They are simple to fit, the grease seems a bit 'sticky' but that seems to be an American thing.
The actual performance is very 'sudden' even snappy like a gas-ram, but the accuracy of the Vortek 97K I have is easily on a par with my 77K which is fitted with a TBT kit, which is softer shooting, like a vibration-free standard system.
Depends what your preference in in terms of a shot-cycle.