Myself, i like to use 300g bullets for all my hunting. The only time i haven't, is when i've used the 270g 44 caliber Gold Dot. I don't really have 'strong' reasons for doing this, but it is what i do.
The 300g bullets usually have a better ballistic coefficient than the lighter bullets, and that is a good reason to use them in my mind. I have never seen any evidence that they are 'too' heavy for deer. When i hunt in Montana there is a chance i will have an Elk tag, and there isn't much doubt that a 300g bullet would be better than a lighter one for these big animal. Using 300 all the time simplifies my sighting in, because i don't have to sight in for different weight bullets when i hunt different animal. Using the heavier bullet makes sense to me when i look at the 50 caliber hole in the end of the barrel.