I have used all of them , TOMTOM, GarminXT and Igo8. I think Garmin has the most POIs of any of the packages. Also Garmin XT is the only one that actually shows my street correctly . I live on a circle and TOMTOM, IGO8 show it as desd end st... Only thing i dont like with Garminxt is its refresh rate its not smooth like the others. Your car looks like its jerking along the screen . Also I like adding my own POIs for trips . Garmin was real easiy to do this.. If i had to rate them i would put them in this order 1.Garmin, 2.IGO8, 3 TOMTOM...
But that just my 2 cents
And yes there is a way to put the GarminXT on a diff chip I had a tech support person help me move it to a 8 gig chip ( he said he wasnt supposed to but helped anyway) .