The best there is .. but not a miracle
On the occasions I use repellent this is all I use. Its 99% DEET so only a couple sprays on the back and a couple on the front will work.
The effectiveness of this product is more a function of duration than quantity. Its about 90% effective for the first 3-4 hours in the swamps. Use a small amount every few hours in intense mosquito conditions.
Spray it on your clothes. You do not want this "stuff" directly on your skin. Especially in sweaty conditions and especially if you are susceptible to heat rash.
Its effectiveness against ticks is highly questionable.
This product is 110 times better than getting all greasy with OFF. Apply it to your clothes not your skin.