I have tried both, and I prefer the heavy whipping cream. Yes, it's harder to drink, but I like the way it affects weight gain. With boost, I was developing more of a hard pot belly, with lots of visceral fat. Now that I'm gaining with heavy whipping cream, by belly is soft, flabby, and jiggly.
The trick with heavy whipping cream is to avoid drinking too much. The body can only absorb about 1,000 calories of fat at a time. I also drink some juice as a chaser. I make sure to drink juice that has no added sugars, since I'm not trying to gain weight by spiking my sugar levels.
During gaining cycles, I'll drink the heavy whipping cream 4 times per day, spaced at least 3 1/2 hours apart. This combination has worked better for me than anything else I have tried.
I wish you the best of luck in your gaining, and hope you're able to achieve your goal.
2 years