UPDATE: I used to be a customer of RapidSSL 3 years ago, when they were one of the first providers of Wildcard SSL certs at a decent cost.
They were a great company with really good customer service, and a good price.
TODAY: I have just tried them today, and been thoroughly screwed. I STRONGLY recommend not to use them. I am really unhappy, because now I have to try and find a new SSL cert provider, and I *liked* them before. It was nice that they would phone you back directly - and usually within 30 seconds of you reporting a problem.
Here's what happened today:
1. Tried to buy certs for two domains
2. They processed my order, took the money from my CC
3. Their system crashed when I uploaded my CSR
4. I phoned them to ask them the problem; after going through menus, a recorded message said they no longer do support on the phone, said I had to use live chat on their site
5. I used the live chat. The first person I spoke to - Chase - said nothing, then it said they had crashed, and Chase came back after 5 minutes
6. Chase then quit to be replaced by "someone from Tech Support"
7. It took more close to 10 minutes for anyone from tech support to come along
8. They asked me for a "Screenshot" and to email my CSR to their email address. A screenshot was of course stupid given that I had reported the exact error from their system. But I sent the email
9. 1 hour later: no response from the tech support email
10. I go back on live chat, ask what is going on
11. Eventually, someone from tech support comes on and say they don't reply to emails for 12 hours at the moment (WTF! TWELvE HOURS!)
12. So, I ask for a refund
13. NOW they deny having taken my money
14. I give them my order number from their confirmation email + order conifrmation webpage (which contained the words: "Your credit card has been charged USD 56 ")
15. They now start to deny that their company is involved, claim I used a reseller.
16. I ask the name of their company (rapidssl), and point out that I went direct to their website because I was a preious customer, I definitely did not use a reseller
17. They continue to deny having taken any money, and refuse to do anything about it. They say that IF I can provide evidence that they took the money, and mail them that evdience, then they might be able to do something. WTF?!
18. I phone my credit card company: they conifrn that the $56 charge has been made on my card.
Final step: I've informed my credit card company of all the above. If the charge isn't removed by this time next week, my credit card company will pass it over to their card-fraud department. RapidSSL: sad, very sad. Definitely NOT the same quality company it was when I first used them years ago

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NB: I'm now googling for other SSL cert provider recommendations, and found this page. I was so unhappy about my experience today that I registered with this forum just to let other people know what the ****ers are like now (september 2008).