Please explain what you mean by reliable. Speed of payment to the trader? Support against questionable chargeback claims? Are you asserting some don't actually pay you at all?
Quality in the mind of traders seems to depend upon the average ticket price of what you're selling. The lower end all seem to have their problems - Paypal, Nochex, for instance - but at the higher end it's harder to get an account in the first place and the charges are seemingly prohibitive for the new trader. Fine if you can show a proven track record and the higher end, on the whole, have policies which are coherent and easy to work with.
Barclays and Streamline seem to have moved into contention among my clients, whereas a couple of years ago they were considered too expensive. Worldpay have been going down steadily over at least three years. SecPay are still highly regarded by techies and clients alike as a payment gateway.
There are so many of them and their relative offers change over time. It appears to be worth shopping around, if you have been trading long enough and successfully enough to have options, avoid lock-ins and don't be afraid to switch when the time is right.
Sadly for most new traders, they raise this question in high expectations only to find their options are very limited anyway.