Much depends on the intonation and the age. For example, my dad is over 60 and close frinds and relatives call him Павлуша or (дядя) Паша. However when someone younger or not that close uses the diminutive, I personally find it irritating or condending.

As for me, "Павлик, Паша, Павлуша, Пашута\Пашутка, Паня" definitely imply fond attitude to a person, while calling someone as "Павлентий" in the most cases shows your condescension. However I agree with Yana it always depends on context and intonation.

Well, in Russian almost every diminutive of the name, dependently on context and intonation, can express sarcasm o condescension. As for those forms for the name Павлик there is no any difference between them, it only depends on the family, friends or co-workers. Some people can use Павлуша, others Павлуня or Павлуся, and so on.