hmm, new bluetooth gps user here.. as for ur question
a)for me, i think is worth and connection are always available if u r in open space regardless where u are
b)never directed me to one way road before though.. nontheless, if u see a one way road, juz purposely miss the junction n new route will be calculated to u in no time
c)i think that is how many satelite ur gps can capture.. but AFAIK, it doesnt matter as u juz need a minimum of 3-4satelites to work.. n max satelite u will get is 12.. i juz think la coz the earth is sphere, covered with 24 satelites.. if we on the gps, i think only can get half of the sphere which is 12 satelites.. i think those good chipset got faster refresh/update time..
if u were to use bt gps, the only draw back is u need to bring 2 device and charge diffrently.. other than that, i think it is perfect

do you have a smart phone? cause i think somehow waze apps is doing better than my garmin GPS. my garmin took me to toll plaza where there's an alternative and shorter path to my destination.

waze also have another pro which is determining the traffic condition and learns to alter your route with less traffic in shorter time. best of all, the app is FREE!

do you have a smart phone? cause i think somehow waze apps is doing better than my garmin GPS. my garmin took me to toll plaza where there's an alternative and shorter path to my destination.

waze also have another pro which is determining the traffic condition and learns to alter your route with less traffic in shorter time. best of all, the app is FREE!

and then u should prepare to pay for the data charge....