April is considered Magic Season in DVC which means it costs more points (usually) per night than other times of the year. So I would do the math to see how much it'll actually save you to rent vs going directly through Disney. It also depends on the kind of unit you want. I think you generally save more with a studio than you would with a 1 or 2 bedroom. Again, do the math. If you visit MouseSavers and looks at the historical discounts, you can get an idea of what discount will be offered at the time you are thinking (not guaranteed). The other thing is you have to commit early. It's hard to get a last minute rental, especially studios.
I have rented twice (stayed once - next stay is in May) and I had a good experience. Both were rented directly from the DVC owner (found on here and another board) which is usually cheaper. I did my research and got references, so I knew they were reputable. The owner I'm working with now only required a 25% deposit up front, which I find to be rare.