I daily drove mine for about 6 months while my 93 Civic was down for a blown head gasket and I had other projects taking up the garage. 8600GVW K25 with 350/TH400/NP205 and 4.10's running on 35x12.5" tires. It definitely isn't winning any eco awards.
Hopefully I'll get a bit better fuel economy when I switch to the MPFI 454/4L80 and can get the revs down while being able to keep the AFR at peak efficiency. I use it for hunting/hauling/towing most of the time, so the reliability of the EFI with the added grunt of the Gen VI 454 should make it a much more enjoyable and useful hauler, even if I don't get any improvement in fuel economy. The 93 Civic gets about 30mpg, so that's nice