I have two Garmin Nuvi (650,760) units, and my son has one(760). All three work flawlessly. They never lock up or ever have a problem finding their way, but I DO update the maps every year....
As for displaying the max speed on the road you are on, I have never heard of that, or seen that on any U.S. GPS unit. Not that it does not exist, just never seen it. Could be a UK thing....
There is the TomTom map issue though. TomTom uses a different mapping company than Garmin, and up until this year, TomToms maps were way inferior to Garmins. I know TomTom was working to fix this issue, but do not know if it has happened yet.
The issue PVR had with junctions.. I think it comes down to resolution. The default zoom level on the Garmin is further out. So you MAY have to press the + (zoom in) button to zoom your display in to get a better feel for your area. eg, differentiate your streets better.
I do like the BlueTooth feature on my Gamins. I don't have pull my phone out to make or answer a phone call....
It really all comes down to user preferences. If you are use to a TomTom, you will find all kinds of faults with the Garmin units and vice versa....
I have owned a Cobra, TomTom, Magellan and of course a Garmin GPS units. I like the Garmin best....
Just my 2Cents....