It would be a great ride, with the steel feel. I'd go for it, as you could probably lose the difference in weight. It wouldn't be that noticable and would have a great feel over low end aluminium frames, plus it is stronger. I have a steel singlespeed which isn't light (about 3.5-4kg for the frame and fork) but is a great ride and very fun. The carbon fork included isn't a heavy one, but it has an aluminium steerer so it won't be light. That aside, it would build up to be a great bike, probably under 10kg (22lb) depending on the components.