I'm personally not sure what I like best yet. I like the idea of the Sun slinger since its all self contained and at a good price point
I wold have to say Sunslinger as well (caveat, never personally used a 12v system) I have a sunslinger that I bought in 2002 iirc, has ran non-stop. I have had to add a new solar panel and replaced the motor at about 10 years. I have friends that have Sunslingers that are older than mine.
I had considered a 12v when we where on a lease (14 of us) The guys with the 12v loved the power, but changed to the sunslinger for easier maintenance. Like I said, I never used a 12v, haven't needed to venture into it, I just took what the other member liked and went with it. Been a great decision so far and I will be buying another sunslinger for a new spot soon.