Chevy & GMC Vans

The last few years I've been using Peak Global lifetime antifreeze in my truck. I like that you can mix it with any other antifreeze and it's guaranteed to last "for as long as you own your vehicle".
http://www.peakantifreeze.com/peak_global_lifetime.html

A few years ago i flushed the coolant in my truck and refilled it with this stuff. I wasn't having any problems or leaks, i just did it for preventive maintenance that was long overdue, i had never changed it and the truck was 10 years old or so with probably 50,000 miles on it.
Soon after changing the coolant the thermostat died and it started leaking from the radiator and a freeze-out plug on the front of the block (thermostat goes for over $100 from the dealer BTW). It leaked slow at first i and was able to keep it topped up by just adding to the overflow bottle every other week or so. At some point i was underneath it (probably to change the oil) and i could see that every freeze-out plug was leaking somewhat, not enough to drip but enough to leave a trail down the block. So i bought a new radiator and every single coolant hose and freeze-out plug and replaced them all (i had already replaced the thermostat). Everything is working fine now for a few years with no leaks. I'm sure it was no coincidence that after 10 years with no problems that all of that went bad in a week of flushing and changing the coolant but i just chalked it up to the old coolant being in there so long and causing some kind of problem I'm not familiar with.

Then a few weeks ago i drive my 2000 astro to work on a cold day and it didn't seem to heat up quite fast enough. So i put a new AC Delco thermostat in it and used the same coolant. Just two days and roughly 10 miles later the heater core starts to leak into the passenger compartment. It was slow at first but within a day i couldn't even drive it anymore. I don't have any idea how old the astro's coolant was since i pretty much just got it, but i find it odd that both of the cars I've changed to this stuff start falling apart right away.

So I'm curious if anyone has used this stuff and had similar problems.

Interesting... I have four jugs of the stuff (2 for $10 sale) sitting in my garage unused. Maybe they'll stay that way. I wish I could add to the review, but like stated, I haven't used them yet. Anyone else?

My rad is leaking however, on the driver's side. I have 150k on the van and have flushed the cooling system at least twice, maybe three times over this period.