Does anyone here have a portable satellite radio that they use in the car? You know, the kind you buy at Best Buy (not factory installed).

My car came with satellite radio and my husband loves it. I thought that I would get him a portable one for his truck, for Christmas. I'm just wondering how good the antennas are on these radios. Even with my factory antenna I hit blind spots driving past tall buildings or under bridges. Can anyone comment on the portable radios?

Thanks.