Has been horrible.
My first experience was last July and I tried ordering an Alpine head unit. It was located on their website and could be ordered, so I did, along with a unit for my sister. Well, they charged my credit card for my sisters unit and failed to to inform me that they wouldn't be sending me the unit I requested. I finally called them after a week to ask when I could expect shipment and they said there wouldn't be a shipment because they didn't have it in stock. Strike #1.

So, after that fiasco, I ordered another Alpine unit, the CDA-7998 - right when it came out. After a few months, it began to get stuck in the "CD Open" position. So, I sent it in for warranty work; that took 2 months all said and done and there supposedly wasn't anything wrong, but it still does it. Also, upon shipment back, they didn't include the remote and owner's manual I included with it and they've been very unresponsive to my request for new ones saying they've "had difficulty locating" new ones. It was also poorly bundled with the head unit sliding around in the original box with no support. I'm currently trying to get a refund or new unit since this one is shit, but that doesn't lok possible.

I'll never be doing business with them again. :madfawk: for onlinecarstereo.com

I have, however, had good luck with the following businesses:
http://www.thezeb.com
http://www.autotoys.com
http://www.ikesound.com/