Was your Macbook slow when you bought it?
If not, do a complete software rebuild (Back up all you data, ensure you'll be able to reinstall all your required software, reformat your hard drive or delete and recreate all partitions on it, reinstall the MacOS, reinstall your applications, restore your data).
Your Macbook should then be as fast or faster than new, assuming your applications don't include bloatware that slow it down.
The "best" laptop comes in many forms. For me, the best laptop would be one that I got for free that does the job that I want it to do. Like my girlfriend's Lenovo L450 that she got for free a while ago now. It's blistering quick for her needs: web browsing, writing letters and emails.