using sticks with grips will end up being a crutch and will also stunt the growth of the micro adjustment process that you need to adjust when slips happen
everyones sticks slip, twist , move, etc etc......if they didn't that would mean your grip is too tight.
what we need are micro adjustments
for a seasoned player they happen unconsciously ....and often
these adjustments automatically keep the stick at our comfortable balance point without us even realizing it and happen the very split second our hands recognize the weight and balance of the stick change
micro adjustments are difficult to describe in text .....but if I remember correctly Tommy Igoe addresses this in his Hands dvd
very important .......and commonly misunderstood and seldom talked about aspect of drumming
all that being said....I don't think a stick with "grip" will help with your slippage much if at all
and even if it did why would you want to mask a technique problem that should be solved with your own fingers by using rubber dipped sticks ?
this is why I am not a fan of dipped sticks or stick wax...or anything of the sort