[Build Help] What's the best AIO water cooler?

As the title implies, what's the best all in one water cooler on the market at this time?

Ideally, I would like a 280mm rad as i will fit better in the case I plan to buy, however it's not the biggest deal. Also, i'm not too bothered about the fans that come with the cooler, as I will be upgraded them to match the others in my system. I would really appreciate some feedback as i'm really stuck! Thanks!