There is no 'best', as it's so subjective.
More like crossing a threshold......after which it all comes down to what button configuration (number and placement) and ergonomics feel right to you.
Rival 700 could be that mouse for you, or not. As the above mentioned, try several if possible. A local store where you can buy mice and return them if you don't like it (or just want to try something else) is probably worth it here rather than trying to save a few bucks by buying online where returns and exchanges would be a hassle.