I've used it in low volume situations and it does what it's supposed to do for me. I don't know whether your question is/should be about a payment processor tho

I've used it in low volume situations and it does what it's supposed to do for me. I don't know whether your question is/should be about a payment processor though; using PayPal as an invoicing system is fine but is the real question, "Should I be using PayPal?"