How long does it take to reset an iPhone 5?

You mean reboot? It's probably stuck on that screen. Download tiny umbrella and try and get it out of boot. If no luck, put it in DFU and restore it with itunes. Apple won't do anything because it's the jailbreak messing you around. There's a lot of trial and error involved. I've had it where umbrella works, where DFU works and then randomly, I've had it where I had to use a different computer to get it to work. I've also had to change stuff in the registries before. Hate it when this happens, you can never quite tell what the problem is and you should probably say goodbye to your data that's currently on the phone. All I can tell you is that it is probably NOT broken so don't go selling it as broken or a guy like me will buy it cheap and have to muck around with it for a couple of hours and make a nice profit on it.

And no, carrier will make no difference. Won't make a difference unless your phone being CDMA ot GMA (Think that's what they call it :S) is affecting something (which it rarely ever will unless you start using custom or specified IPSWs).

If you are just restoring the phone and there's no problem, it should take about 1-2 mins.... and I just wasted my time writing all that -_- lol

iPhone 5 is popping out in October 2012 and that's a protracted time. So use the KinTwom for now and get the iPhone 4S while eligible for improve in March. You an in a while ell the iPhone 4S and purchase the iPhone 5 while it comes out.

Hold down the sleep/wake button and the home button until it turns off