Answer:
In one word? stunning.
Their are 2 different types of effect: a trip, and an experience. A trip is usually attained by a small hit, its pretty incredible but can be uncomfertable at times, even when your with friends, it should not be taken likely.
Multiple hits will result in an experience, this is the scariest thing i have ever felt, if you want to have an experience be ready to get really really scared, because you will see god, the 5th demension, and you will notice senses that you never felt before (imagine if someone who was blind from birth got to see for the first time, that's what its like for your brain)
Only adviced:
1.do it with friends in a safe, familiar, environment
2. During your trip just keep in mind that it will end
3. Dont have an experience too many times, this isn't a drug that should be taken casually like weed, DONT DRIVE OFF OF IT OR YOU WILL CRASH!!!
good luck and be safe.