Thoughts on Gunk 5-Minute Engine Flush?

I have a 1997 Jeep grand Cherokee loredo with the 4.0 I6 engine. it has 162,000 miles on and i changed the oil on sunday but before i did that, i used Gunk 5-Minute Engine Flush. since my engine is old, it has a lot of sludge, varnish, etc which was making my motor oil dark quickly and burning off a lot oil. now i know its an old engine and that does happen, but when i used the gunk flush, it cleaned it up amazingly, and the oil burn off has been better . i am curious if anyone else has used it and what they think of it?