Definitely Webmoney. Skrill is a reversible payment method and they often lock accounts concerning Bitcointrading.
WM is not the best payment method, better take a closer look to PM and Payeer, but they're at least not returning funds back as they like.
Is any of these providers safe against credit card chargeback? Otherwise everyone could be scammed when the scammer used carding to fund the account or charges back his credit card payment.
On the other hand it would be interesting for normal users paying with it and getting scammed by not receiveing what they paid for. So Skrill, Paypal and WM would be good because the scammed buyer could charge back but PM and Payeer would be a lost cause?
WM & Payeer = Chargeback officially impossible, but in some cases, especially when the fund's origin account was hacked, they may return the money. Both are usually funded by exchangers with either cash or non-reversible payment options, so in 99% of all cases no transfer reversal happen.
PM = Chargeback impossible, even if you contact the support. They don't care at all. This is provably the most safe option to buy & sell BTC as there is really no chance for fraudsters to fund their account with stolen credit cards or bank account data, as they simply don't offer this. And the exchange providers are preventing themselves from such people by ridiculous verification processes.