Do we reincarnate into similar or polar-opposite lives I've read several reports of people remembering past lives. In many cases, in their current life they tend to have a very similar personality, repeat many of the same life patterns and often have many of the same interests they had in their previous life. This would suggest that we incarnate into lives which were similar to our past life, repeating similar karmic patterns.

However, I have also read many sources which claim that we incarnate into life situations which are the complete reverse of our previous life in order to experience the karma 'from the other side' of the situation. For instance, if you were an abuser in a previous life, many claim that in this life you would be the victim of an abuser who was your victim in your past life.

The two paradigms seem rather mutually exclusive. I was wondering if Buddhism could help shed some light on to this.
No matter how you slice it, Buddha said we have been in every situation many times over.  In one sutta said when seeing a wealthy man indulging in all fine things in life and in another sutta crippled man lying in the gutter, we have all been there.  For this reason, it is enough to be tired of samsara.
It is reasonably to assume we have been in every situation and every world many times (except for world of sutavassa-world for non-returners.)