I heard the eXRS radios had trouble syncing and having owned one, they are cheap bubble pack grade.
I would recommend the Motorola DTR. They're just about the same technology but the DTR is digital and is much tougher. eXRS uses analog narrow FM.
Or if you want to save some money, look up Nextel Direct Talk and try to find some i355's, 560's or 570's on eBay.
If they have sim cards, just power up and select DT mode and you have 10 digital simplex channels.