This is reeeally subjective.
I have found drums easier to learn, but I found the movement, coordination, and groove very natural. I'd say guitar is easier at the beginning, but drums very soon after. And much later, guitar is easier again.
Each is better for different reasons:
Drums is better because they're the foundation of the song. The whole sound of the song depends on you. When people are dancing to the music they're dancing to *your* groove. You don't have to worry about learning chords to a new song. If you can hear the song in your head you can pretty much play it - while the other musicians have to know what chords are being played. This makes sitting in and learning new songs easier. You get to sit throughout the entire gig. No full band can have no drummer. You don't need an instrument to "play" - you can play on your lap. You can easily take a drum pad and sticks anywhere and practice your rudiments, sticking, speed and more.
Guitar is better because it's more of a showman's instrument - people remember the guitarist far more than the drummer so your more likely to have a huge career. Guitar licks are remembered, guitarists get more chicks (or dudes), you're at the front of the stage - not buried behind a wall of drums in the back. The guitar is so much more expressive. Between licks and solos, you're featured in just about every song. You can practice without waking the neighbors. At the gig, you can load in and out in one trip - drums are a huge load to carry around with you. You can throw your acoustic over your shoulder and go play at the beach, park, in town, etc. You can play solo gigs or write songs for your girlfriend because your instrument can play melody, harmony and rhythm.
Whatever you decide to learn, learn the heck out of it. If it gets tough, don't be discouraged - just keep practicing. The most talented players didn't just pick up their instrument yesterday, they've been practicing for years and years.