I’ve done limited testing with the XBee Pro 50mW Series 2.5 XBP24-BCIT-004 and it has worked fine. When I first started the sketch the sketch reset a couple of times before it settled down and started sending the data on a regular basis. I had a LED connected to one of the pins which the sketch was using for indicating data collection and I am not sure if this was interfering with the Xbee. That’s one of the reasons why I created the other thread asking for the pin allocations on the Stalker. Another thing I am going to try is disabling the auto reset. Instructions for disabling the reset can be found on the Arduino site at:
http://www.arduino.cc/playground/Main/DisablingAutoResetOnSerialConnection
I’m not sure what you mean by garbage data but lots of time when you get strange characters its a problem with mismatched baud rates. The only testing I have done is at 9600.