The weight difference between the aluminum SOL (10.5 oz) and the SOL Ti (9.8 oz) is less than a ounce. The Al version is actually a bit more efficient heating due to the better thermal conductivity of Al vs Ti, but water will also cool down faster in the AL version due to the same reason. The AL version doesn't have the issue of the burner ring separating (the reason the Ti version was discontinued), and you can cook food directly in the Al version, which Jetboil specifically recommends not doing in the Ti version. For both cost and reliability reasons, the Al version is probably a better bet.