Indeed,
I couldn't believe the difference when I got my 08 Chevy 2500HD last year.
It pulls loads that my old (dead) Full size Blazer used to struggle with. The Blazer got around 12 to 14 mpg empty but about 6 to 8 mpg towing. The Silverado gets 15 or 16 towing and 19 to 20 mpg empty. The power difference in towing is incredible. Around here in So Cal. diesel and regular are about the same price now. I know there's quite a difference in up front purchase cost, but it's worth it to me for all the towing I've been doing every other weekend over the last year alone. It's almost like driving up and back with no load at all.