For reliability and durability, the 2-135 wins hands down. The transmission in that tractor is much tougher than the 2255, and while the Hercules engine is known to drink it's fair share of fuel, the Cat engine isn't going to be much better. Plus the Herc is better lugging motor.

I'm not knocking the 2255, because it will do the job and has that cool factor and collectability. If you're really concerned about fuel consumption, consider stepping up to a White 140 or 145 with the Cummins engine. But be ready to pay for it too.