What is the difference between the anti rubbers and pimples (regardless length)?
That is a question with a very long answer. Try searching through the OOAK forum.
What advantages and disadvantages each has?
SP are the closest to playing with inverted
MP are almost useless in my opinion because they are too much of a compromise between SP and LP
There are many types of LP. Some are good for chopping, Some are good for push blocking.
You could have asked just about the differences between LPs
Anti gets the spin reversal of LPs depending on the exact type. Again, there are many different antis. The German "frictionless" antis have hard rubber and dead sponges whereas the Japanese antis are a little softer. Anti is easier to play with than LP as there are no pips to bend. Also anti rubbers usually have dead sponges that are good flow blocking short and slow down the pace of a rally. This can be done with LP 0X with "soft hands". "Soft hands" is where you hold the paddle more loosely and even draw back the LP to absorb some of the impact and reduce impact speed. A little bit will go a long way and it takes practice to block a loop kill short.
What can each be best used for? Which could be better overall?
SP are good for attacking. SP works well on the BH.
MP are good for covering the paddle.
LP with sponge are good for chopping / defensive. Hitting is tricky.
LP 0X are good for push blocking. Hitting is tricky.
Anti are good for blocking short and slowing down the pace of the rallies. Anti rubber is relative easy to learn how to play with unlike LP but again, hitting is more difficult like with LP.
Anti rubbers don't have pips that bend and change the grip/ spin. This is why anti is easier to play with than LP