I had been using the MaxLife 5W30 in my '80 Firebird FORMULA V8 for the past 3 summers...This spring/summer I bought a 5 qt jug of DEFY 5W30. It certainly has made the engine even more smooth/quieter than the MaxLife, which itself made the engine quiet as well.
I don't particularly want this engine to be too quiet but, it seems to have removed some of that rummble that I love in the exhaust.
Thus far though, I do like the DEFY. Both the MaxLife and the DEFY have reduced the oil drips on the garage floor and the small consumption that I had experienced during the summer.
In the short summer months that I do drive the Firebird(~500+ miles) I had been experiencing about a 1/2 qt loss of oil during those 500 miles but, no more! It stays at the full mark on the dipstick all summer and I have owned this car for 32 years, where it has always lost some oil due to burning. I have fixed many of the leaks over the years(valve cover gaskets etc).
The oil driping(and it was ONLY driping, NOT leaking out), started about 20something years ago but, even before that I always had to add ~1/2 qt during the summer even after an OCI, which I performed each summer. I have to admit that, years ago, I did put on more than 500 miles during the summer. More along the lines of 1000-1500 miles per/summer. TOTAL MILES TO DATE: 39700 miles.
So, I can attest to the HM oils to some degree!