Theme for Product Reviews Website

Paul Here,

I have a website about Product reviews, I am currently using the Generate Press Premium theme. But I am really not satisfied with it. I want to change the theme now. Can somebody help me out in selecting the best theme which is also lightweight & having a good design? You can look at the current design of my website: [].
Also, if I change the theme now, will it affect my whole website structure or not? Guide please.
I will be waiting for the response.
Regards & Thank You