What's Your Priority? Design or Functionality?

I've recently begun to play around with Path of late, a mobile app that has really gained some steam of late. In addition, I've really began to take a shining to Pinterest, something chronicled here, here and here on @arikhanson's blog. What do these things have in common? They both have very clean, minimalistic, beautiful design. The user experience in terms of aesthetic value is amazing, something that keeps people using their apps. (Seriously, Path has one of the cleanest mobile app designs out there). Zeroing in on Pinterest, look at it's functionality. It works great...when it works. Pinterest has a tendency to be very buggy, crashes a lot with many a 503 error. People complain about how slow it runs and often times crashes in peak evening hours. Yet people still swarm to it. Why?

Because it is visually easy on the eyes.

Seriously. If Path ever crashed or acted slow, users would be equally as forgiving. The types of errors and roadblocks that users hit on Pinterest would be completely unacceptable with many other social networks and apps. Nobody would stand for it if Pinterest was ugly. Most users would walk away without thinking twice. However, they don't and I feel design has a lot to do with that.

Path rose to popularity because of its simplicty. Sure. Facebook imposes a friend limit as well (albeit a much higher number) and can be equally lifestreamy. However, Path has two things going for it: it's new enough to not be crowded and it has great design. If it wasn't for the beautiful look that Path provides on your mobile device, most people wouldn't give it a second look. Users would cast it aside as "just another social network." But they don't.

I truly believe, at the end of the day, the apps and/or sites that see the most success are the ones that look the coolest.

I have never liked any app/website enough to deal with how often it breaks as pinterest

— elysa rice (@elysa) December 14, 2011

Which raises my question: in the initial "out of the box" launch of an app, which do you believe is more important: looks or functionality? Do you think more people will forgive an app for working awesome but looking so-so or be more forgiving of an app that struggles with functionality but has a high aesthetic appeal?

Design or raw functionality? What do you think leads to greater success? Let me know in the comments :)