RTi Sat Nav - any good?

[tvrforever]

Ok so I've been a TomTom user for the last 6 years or so and found them to be great but now looking to change to a new S80 and Satnav has come up...

At the moment all the new S80s (except the 2.0D) come with the RTi system as standard at no extra cost, however :-
1) Is the RTI system any good compared to TomTom?
2) How often are the maps updated and at what cost?
3) Can I transfer my current TTG POIs onto the RTI? (as i have all my normal destinations in a POI)
4) Can I get a speed-camera POI on this? (currently use PocketGPSWorld)

For the 2.0D I also have the option of getting a Garmin 760 fitted by Volvo for £460 hardwired re a design agreement they have between Volvo & Garmin - any experiences etc?

Or should I stick with TomTom and work out how to get power to it (as S80 power socket is in centre console between seats)?

Any thoughts / experiences much appreciated...