I like cylinder shaped, medium-hard density felt beaters like this one. The weight distribution (all around the shaft) allows for balanced momentum when performing the hit and when collecting the rebound.
This beater is very well designed in that regard.
I tend to avoid burying the beater it at all times because I hate that kind of sound and the waste of energy, but apparently I do apply a lot of force to the strokes. Which is maybe why..
..after about 150 gigs I snapped the shaft in two.
Previous to this Sonor, I have been playing for 18 years with an old Yamaha beater, which came with my very first (and cheap) drumkit. Its shaft is probably made of hardened steel because it has never ever bent. Obviously, they don't make these anymore....
I do love Sonor a lot, but maybe they could take a bit more care when sourcing the metal for those parts which have to withstand a lot of stress