This Sony NVX can't really be described as "handheld and portable" as it requires power supply from cigarette socket.I have had it for over 2 years now,and apart from the usual "diversions",have been very happy and confident with her.I say her as she is called "Deidre"! She took me to the other side of Geneva 2 years ago,with only 1 hitch when there was a new ring road around a town which she didn''t recognise.I purchased it from a large retailer as it was on on offer,and actually got a refund 2 weeks later when they had reduced it further[Probably because it was obsolete.]As I am a caravanner I have found it invaluable negotiating the roads in Devon and Cornwall and Wales. I am disappointed in the upgrades,as I have had a roundabout near me for a long time,and she doesn''t know it''s there!