The debate between LISS and HIIT cardio is always a hot topic. The supposed benefits of LISS is that it promotes "fat" burning, because of the slower pace. HIIT is said to breakdown muscle tissue because it is more physically demanding. There is soo much information regarding fat oxidation levels, afterburn, blah blah blah... For me, I'm taking a break from my normal couch to 5k type cardio, because of a stress fracture in my foot. 300+ lbs beating the hell out of a treadmill will do that to you. So, I'm walking at a slower pace at a high incline on an empty stomach first thing in the morning, until the foot feels better.
Until someone can show proof that actual muscle is either damaged / lost from HIIT, then I would much rather only spend 30 minutes on cardio than an 45-1hr. In the end it's calories in/ calories out.