Before having the rrs, on my old P38, I went through 3 TomTom and they are great, easy to use and all but the main issue for me was that, the reason I went through 3 of them is that I kept on having someone breaking a window and stealing it.... and yes, the unit was hidden in the car out of view...what gives it away it the marks left by the stand on the windscreen... So now, will only got for factory fittted one...
I also use a GPS software on my iphone (waiting for the TomTom one sometime this summer) for use in rental car etc... Range Rover Vogue ‘17 TDV6

Gone: Range Rover Vogue '11 4.4TDV8, Range Rover Sport ‘59, Range Rover Sport ‘56

Over on Freel2 there is a thread about integrating various portable SatNavs into the empty slot in the dash - some of the guys over there have done really neat jobs of hiding all the cables and making surrounds that match the rest of the dash. 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW