Once you've gotten over the great hardware, Garmin bowls you over again. The Nuvi 3790T builds on the already considerable strengths of its user interface, making it simpler, smarter and even more feature-packed than before.
From the startup screen to the submenus, you're presented with big, bold buttons and beautiful graphics that make the user interface a breeze to find your way around.
The interface as a whole looks like it was designed by someone with a particularly strong iPhone fetish – only the results are even more spectacular, especially when teamed with the high-resolution display.
To give you just three examples: you get 3D terrain detail (hills, valleys, etc), PhotoReal representations of junctions that show you what the road looks like ahead and, of course, lots of lickable eye-candy buttons.
But the Garmin Nuvi 3790T isn't all surface sheen. Delve deeper and you'll find nuRoute with Traffic Trends and myTrends – Garmin's equivalent of IQ Routes and HD Traffic.
nuRoutes works out the best route for you depending destination and time of day, while also taking into account your preferred driving style.
Better still, route calculation is quick, and the system is intelligent enough to adapt should you choose to go off-route.
Once it realises that you're ignoring its nagging requests to get back on the route it's chosen, it plots another based on the real one you've decided to pick instead. Not many sat-nav systems are quite so quick on the uptake.
Other goodies? There are oodles of them. One licence-saver is the way the Nuvi 3790T flashes up Cyclops safety camera alerts on screen – they pop up in a black dialogue box if you're doing the speed limit and then pop up again in red if you over-do it.
The dialogue boxes are useful in another way – they tell you whether it's a red light camera, mobile camera or fixed camera you should be worried about, for example.
Points of Interest is another area where the Garmin Nuvi 3790T scores very highly. While lesser sat navs are happy to serve you with a list of fast food establishments when it comes to finding local restaurants, the Nuvi 3790T asks you what kinds of food you'd like to eat – from American to Mexican.
Points of Interest are also helpfully presented in logical categories: the Transit one is especially useful if you're trying to find a train station or airport, for example.
And because you can switch between being a car driver and a pedestrian, the Nuvi 3790T can continue to plot your route on foot. It can even help you find your car again using Park Position Recall.
But it's out on the road that the Garmin Nuvi 3790T impresses most. It surprised us with the route it took to our test destination, picking roads we'd never have dreamed of travelling on before.
The thing is, it was right. The route it picked was clever, the roads were practically empty and we managed to miss most of the jams.
The PhotoReal representation of one really tricky junction (where two motorways and local roads merged into each other) was really clear and easy to understand. The whole thing was such a doddle to use, we spent most of our time grinning like idiots.
We only have one real complaint. Like the Mio Navman 575, the Garmin Nuvi 3790T is afflicted with a horrible robot lady voice who speaks through a surprisingly poor speaker that easily distorts once you crank the volume.
Weirder still is the accent she uses. Part West Country, part German, part Geordie. Somehow you can't imagine Angelina having trouble like that.