I had a look at the Segal website. They look like reasonably nice bikes, but for making such a big deal about weight, they're nothing special. They claim 1175g for a frame (what size?). That's maybe 150g heavier than a top-notch AL frame and 150g lighter than a top-notch steel frame. It's about 300 grams heavier than a very good carbon frame.

There are many different ways to measure a bike's value, and weight is relatively low down on the list for me. If it rides nice, then that is much, much more important. I've never ridden a mag frame, so I can't comment on that. However, for all of you that comment on how light a mag frame is, I think you might need a little reality check. Like I said initially, the specific stiffness and specific strength of most bike materials are frustratingly similar. Carbon being the outlier. There just aren't big gains to be found on the scales when it comes to bike construction.