Is 3g practical over highspeed internet?

I currently have sbc yahoo dsl, but am currious and consindering a 3g network. I read about a 3g router that you connect a 3g card into and bam you have wireless wireless (not a typo) internet. Me and my friends are going on a long summer trip in our own bus and we wondering if this would be practical if we totally switched to a 3g network for home and for our trip.