HP iPAQ hw6920 Mobile Messenger With Garmin Mobile XT

 

I am thinking of getting a used HP iPAQ hw6920 Mobile Messenger http://www.hp.com/hpinfo/newsroom/press_kits/2006/mobility/d...
http://h18000.www1.hp.com/products/quickspecs/12352_div/1235...
and installing Garmin Mobile XT https://buy.garmin.com/shop/shop.do?pID=11413#featureTab
I am just wondering how this might compare to using a standalone GPS. I have read mixed reviews about the HP iPAQ from istes like this http://www.mobiletechreview.com/HP-iPAQ-hw6915.htm My big desires is to have an all in one unit that is a GPS, cell phone, and wifi without breaking the bank.