Hi at the moment I use studiopress but sometime I want change things it is hard without coding knowledge
So what you think is better for seo and future
Elegant themes or studiopress
both themes will work great and has advantages and disadvantages.
studiopress is great if you are a developer and need a pretty neat and fast loading theme.
elegant themes is all about customization and aesthetics you can have full control over them.
Also try considering thrive themes they are pretty focused on conversions.If you are more focused on designs and customization then give avada theme a try. i have found them easy to use than elegant themes.