Speaking from personal experience, it's FREAKING AMAZING!!! It can be hard at the same time though. But GOD it just FEELS SO GOOD. Like you're on cloud nine all of the time. And when your dual isn't around, you think about them quite a bit (which is kinda annoying, but considering how good you feel all of the time, it's an easy trade). However, it can be hard to get to that point of dualization and there are a lot of 'bumps' along the road. But it gets easier the more experience you have with duals.
From what I understand, duality between socionics types ending in 'p' is different from duality between types ending in 'j'. Being a socionics 'p' type, I can tell you what duality is like for types with dominant perceiving functions. It's like a freaky dance of opposites and you kinda become rhythmically in love/obsessed with each other. When one person is loving on the other, the second person will be like "eek, get away!" and if the first person backs away, then the second person will start loving on the first. It's very dynamic. BUT... it can be damn hard to make it work in a romantic relationship. Since everything is SUPER INTENSE (the good feelings and the bad feelings), it's easy to just want to be done with it. But as long as you're just looking for a good experience and not trying to find the solution to all of life's problems through love and duality, you should be ok.