The GeoTrust ones work fine. They are just as compatible as Thawte. Just make sure you aren't getting the QuickSSL version they aren't as compatible as the normal ones. I think quick SSL only is compatible with about 90% of the browser market. However with QuickSSL you don't have to fax any documentation in. You get it in a few hours. With the regular GeoTrust you need to fax in your biz documents and wait a day or two.
If you take a look at a lot of fortune 500 companies -- they are running QuickSSL (internally & externally). My feeling is that it is growing faster than any SSL cert out there --- it is definitely the fastest growing product we have.....
Anyway, I am not here to advertise. I like the feedback -- we want to keep making our products better and I am pretty happy with QuickSSL right now.
Those are wildcard certs that secure multiple domains. We have them priced at $500. We have not changed that price in a couple years. The reason it is so high is that we have some folks securing hundreds of sites off the same wildcard.
What are you trying to do? Maybe I can suggest a better way to get to the same result.