AdSense is very reliable for payments, I've been an adsense publisher since 2003 and they have ALWAYS paid me on time, usually less than 30 days after the end of the month.
The only two things I am not so happy with are:
- no payments via PayPal
- no way to transfert adsense money into adwords credits, in order to use adsense earnings to advertize on adwords without having to use credit card or banks at all.
I hope someday this will change but I doubt so, they could have done it years ago, so if they didn't implement it, I'm not sure why they would do it now..