No problem here with Sparkpool.
Wallet needs to be online, like they state on the website, then you click on the Extract button on the pool, and the coins move to you're wallet.
It's as simple as that.
They pay out once a day.
edit : Waiting for Leafpool to be ready...
i know, my wallet was open like their instructions.
but i don't control power company, and computer died.
this is very bad idea the online payment, imagine you pay someone and their wallet offline, you don't get product.
or if someone pay you and your power or internet is bad, you don't get money.
are the coins lost forever or going back to the pool wallet ? will they try payment again or my coins are lost forever ?