There's something about a nice warm orangey/brown colour.
I'm almost tempted to go naturalish now!
EDIT: Just did a quick google about for reviews, a few people have said that they left it on for longer than the 15 minutes and it lasted about 5-6 weeks. Doesn't sound too awful, also it's about £2.99 online. Seriously considering trying it after I graduate and have to try and get a proper job.