Are you basing your personally preference with what's the most popular?
Fast food power rankings, bro.
1 - Service
2 - Presence (how many locations)
3 - Price
4 - Availability (hours open)
5 - and most importantly - Consistency
When you put all these together, no one touches McDonald's. My favorite fast food burger is probably A&W, but I know someone in Florida won't know what the fuck that is. Five Guys has a great burger, but their price point puts them way out of contention and their service is eye wateringly slow. They don't really qualify as fast food as all. They're more like a sit down restaurant with shitty decor and no servers.
p.s. I am regarded as somewhat of an authority on burgers as I eat considerably more of them than anyone else I've ever heard of. It's almost shameful.