It is not reliable for determining whether or not a work email address is valid. I tried several of my customer's work email address, which I know are valid, and I tried my own email address; all returned email_disabled. It returned 'ok' for my personal Gmail account and a few friends' personal email addresses.
I absolutly don't suggest them! I have 700k credits in my account. But there are some problems in my account. I can't verify any files. I wrote them about this problem. They only says "thanks for your patient, we will help you as soon as possible". They didn't help me about anything for 1 week! I am really so angry. I can send my chat script with them to anyone who want to see this. I have credits but I can't provide any services to my customers because of them.
Been using it for about 1 year and really happy over the results so far, The interface is clean and easy to use, no issues with them.
All in all, probably the best price to quality ratio in the market
