I have had a Giga for probably around 10 years and it's still going strong! Definately get the Piezo. In response to some of the other questions:
1) Fuel Consumption, I once read that a Large Cannister (220 grams) will boil around 24 to 28 liters of water (3 season high sierra trips). I've used this as a guide and found it to be an accurate reference. One other note, in addition to using some kind of windscreen, is keeping the Fuel warm, it will increase performance. I usually keep the stove in my tent and on cold mornings I'll even throw the cannister in my sleeping bag to warm it up before using.
2) Differenct Types of Fuel, I've used MSR and Primus without any problems or noticable differences.