Before I bought the theme I did some research on the internet and found out that people who used Thesis were very enthusiastic about it. Thesis is extremely flexible, good for SEO and support from DIY Themes (the theme creators) is very good as well. Thesis is more than just a WordPress theme. The creators refer to it as a framework, which can be customized in any way you would like.
Make sure you do things from your heart, with passion and true intention and do not use tricks to get what you want. In the end people will know you are faking it and you will have to bear the consequences.