What's better, a cast iron pump or an aluminum one that has cast iron sleves? I notice that most all major compressor mfgs. still use cast iron and they are generally labled as "extreme duty" type pumps, but are the newer style aluminum alloy pumps better? I've heard some "hype" about the craftsman compressor I have below, but would you pick it over the other one I have pictured? Lets assume that the price is almost the same for either. Both work on 110 and 220 volt. Campbell Hausfeld 2 HP 26 Gallon Compressor Heavy duty cast iron oil-lubricated, twin-cylinder pump powers a variety of tools for the serious do-it-yourselfer. Product life up to 5,000 hours. 2 running HP motor capable of running on either 120 or 240 volts. 26 gallon tank. Craftsman Professional 25 gal. Air Compressor, 2 hp, Horizontal Tank Single stage pump compressors air in 2 steps for more efficient and cooler operation 2 cylinder Oil Lube Pump with cast-iron sleeves and automotive pistons and rings Durable construction and a lower oil consumption for longer pump life Aluminum fanned crank case and a balanced Flywheel for improved heat dissipation.