Axel,
I think we are all agreed that discharging to ZERO and below, whilst helping increase power, does so very temporarily, so a discharger that doesn't give you any choice is not such a good idea. You don't really want to dead short or discharge to zero all the time, unless someone else is paying for your cells.
I have tried quite a few different discharging devices and find the Novak Smart Tray best and most versatile. It allows you to discharge just as you please. And you can also dead short with it if you like.
I don't know of any other that is so versatile. I think the biggest proof of this is our own team performance. My son has just won his 7th National title, using just 3 packs of Corally GP3300s for the 30 race series with his mod TC4. At the end of the season, the cells are still as good as they were in the beginning. I monitor them regularly.
And Josh's cells from last season were used this season by a young lad racing in super stock, whose TC3 was more often than not the quickest car in the class.
Just proves that good care for your cells is the trick.