neutering my shih tzu

Question
My pup is 8 month.  I was going to get it neutered, but I never did.  Do you recommend me doing this?  Many have said he will have problems once he goes into heat?  What is your take on this?

Answer
He is a Male I take it? then he is already past sexual maturity(starts at 5 months). Neutering pervents cocking the leg indoors to makr his territory and stops him getting out of the yard to go find a bitch to mate with, the dog cant get testical cancer if he has no tests either of course so thats another plus.