Navman iCN 550 -

I already own a Navman iCN635 and I have now acquired a NAVMAN 550TM (£399 from Comet) which comes with street lavel maps of all Western Europe on a hard disk. Build quality not quite as good as the 635 (made in china whereas 635 made in NZ), rattles slightly - probably the hard disk housing but has an internal rechargeable battery which lasts about 2.5 to 3 hours. One minor problem (on both models) - although it is possible to import up to 25 POI files (speed cams etc,) only 16 can be made 'active', this restriction is not documented as far as I can find.
The 550 has a touch screen and it is easier to set up a destination than the 635 but the screen is smaller and seems to suffer more from reflective glare than the 635.
The 550 came with a Traffic module but to use it, you have to drape a wire aerial across your windscreen. The quality of the traffic reports is dependent on FM Radio RDS-TMC data and seems to be pretty unreliable. On a journey from Nottingham to Luton (M1 J25 to J10) it announced a traffic event and irritatingly recalculated a new route every 20 or 30 seconds from Junction 16 downwards. Although I was already aware of the problem (major roadworks from J10 to J6) I allowed the system to override my better judgment and ended up in a traffic queue from Toddington services onwards. If I had used my OWN judgment, I would have left the motorway at J12.
Apart from that - The 635 has already given sterling service whilst driving in the UK, France and Spain, and, except for the traffic module, so far, I am confident that the 550 will do the same.