I have a Garmin which was no better than the TT, in fact the TT was pretty good overall, it had many features that the latest system doesn't.
What I found disappointing was the smaller screen and poorer screen resolution compared to my 2009 Xtrail nav which was great. And no TCM, you had to pay for live traffic, and it originally had a connection issue, later sorted with a TT software upgrade.
New system works has a 7" screen but although full post codes can be used, the system for some strange reason will not offer ALL the street numbers? The TT did.
With both cars I've had phone connection issues which is separate to the nav.