I’ve a woolich racing qs on my 08 which works very well and cordona pq8 on a couple of other bikes that are very good as well.
Track or road bike? For the track it depends how quick you are, but they're not essential mod. For the Road they sound good on gear changes, but definitely not need.
I've a Translogic, a little pricey but I f&*king love it. Had Healtech on my Aprilia, that was good but was a little annoying on times as it works both ways, so if you knock the lever down it cuts the engine. They may have ironed this out on any later models. Overall the Healtech was good bang for buck but the Translogic is something else!