What is the best broadhead for deer and best grain

Ask 20 different bowhunters and you'll likely get 20 different answers to this question.  It's hard to say what the "best" broadhead is as it's a matter of personal preference.  Whatever shoots good for you is always the best option.  Shot placement is a lot more important than broadhead design.  100 grains is by far the most popular weight for broadheads.