Thawte is a brand that is known over 240 different countries. It was bought by Symantec n 2000 and is part of their security family. With a big and popular company such as Symantec behind them, you can really trust Thawte to provide you with the security that you need. The company even have a multi lingual help service which means that you will be able to chat or email them with your queries and know that they will be able to help you.
Like other SSL certification companies they sell a selection of certificates. Some can be issued very quickly and provide lower levels of security and others take longer and can provide the type of encryption required by sites exchanging financial information.
As one of the oldest SSL providers in the world, it has a well-known name and a good reputation. Of course, to get this sort of quality, you will end up paying more money. However, you will be able to gain a lot from getting protection from Thawte. You will have reassurance for your customers that you are using a well-known brand and that should encourage them to trust you and make more purchases from your website.