For new bike frame fabrication you could use MIG, but TIG would be better, and for repair TIG will be the way to go for sure. Can't say anything about pulsed MIG as I've never used it, but most of the companies that make them say extreme high speed welding is the big selling point. Something more suited to a production shop. One thing that does attract me, is some of the pulse on pulse MIG comes out looking much like TIG welds, very clean and even with no spatter to clean up.