I own (and sell) the Titan jack.
I have had zero problems with it, including lifting my 1994 GMC 2500 Suburban, which already has 6" of lift. If I place the jack at centerline, I can lift one side of the truck at a time, no problems.
It also does one thing a Hi-Lift cannot; It will lift you easily, while in very wet mud. It literally squeezes the water outward from underneath, and settles on the the mud, then lifts. It works the same way with soft sand, too, which is Kryptonite to a traditional jack, even with the lower support plate.
I will say, though, that I don't care for using the exhaust, as it's time-consuming and messy. My Suburban has on-board air, so it's easier and cleaner to use the compressor adaptor. I build a little vortex adaptor as well, and I can evacuate the jack of air in seconds, too.
However, for test purposes, when connected to the 3" exhaust on my 5.7l GMC, it takes about one minute to fill to completion.
On the E, once I remove the tailpipe 'beauty tip', it takes about five minutes.
Both tests done at idle, by the way.
I also keep a traditional Hi-Lift in the Suburban, as it can be used in so many other ways, too.