Summary: The Alpine CDE-124SXM is a great value for those who want to upgrade their car stereo with USB/iPod connectivity while adding very good SiriusXM connectivity.
Pros: The Alpine CDE-124SXM combines a SiriusXM Satellite Radio receiver and a decent CD/USB receiver in one value-priced package. The Instant Replay feature can pause live satellite broadcasts for up to half an hour.
Cons: The Instant Replay function doesn't work when the vehicle is powered down, somewhat limiting its usefulness. The extremely basic CD receiver limits system expandability.