I have not used them before. They are not much popular and have a low user base. Payeer conversion rates are high. I would suggest converting Payeer to OKpay and then bitcoin. Payeer to OKpay average conversion is $1:0.92. If you have a big amount in your Payeer account and if you have the option to withdraw it to your bank account, then that would be better.

Or, you can also try the currency exchange section, https://bitcointalk.org/index.php?board=53.0