I've not used JB since iOS 4 and never a tethered JB. Personally I wouldn't as JBs, or the apps, are not always stable and can mean that you need to reboot the phone occasionally (sometimes often). I couldn't take the risk of this happening if I was away from home and not being able to use my phone until I could get back and plug it in to boot tethered. I seem to remember something about a soft boot coming about some time ago, it did something like allow the phone to boot back to some sort of limited default state so you could at least access some features like make phone calls and send messages.
As far as I'm aware there is no untethered JB available for any iOS version over 5.1.1 and nothing for the 5 or iPad 3rd/4th gen iPad.