Address finding is one more aspect that has seen a tweak for the better. You can now enter a post code straight away when you hit the address screen, instead of having to select a city first. However, if you're locating your destination by address, the data entry is still counter-intuitive: city first, street next and then finally street number.
Of course the C520t is more than just a bunch of improvements and it retains a lot of the features that made many of Mio’s previous navigation products such great value for money. As with all of the company’s products you get street-level mapping for nigh on the whole of Europe. These maps are preinstalled on the C520t, so no fiddling about uploading maps from the supplied CD – everything just fits in the device's built-in 1GB ROM. And there's a speed camera warning database with free updates provided for a year after purchase.
The C520t is also very good at providing driving instructions. Rarely did I find its TeleAtlas maps to be inaccurate, even in central London. Audio cues were clear and unambiguous, while the onscreen information and next-turn icons were always extremely helpful. It's also pretty snappy at calculating routes, a feature that comes in especially useful when you stray off route or emerge from a tunnel and need rapid recalculation.
That's not all. You can also use the device as a Bluetooth speaker phone while driving, upload your contacts to the POI database and use them in route planning, plus there's a photo viewer and an MP3 player too. Disappointingly, the headphones socket isn't the standard 3.5mm job so a regular pair of headphones won’t fit.
It isn't all good news for the C520t, however. In fact for all of the improvements it seems that a few serious drawbacks have crept in as well. A bit like trying to produce a super-efficient green car that produces no CO2, but belches out black smoke full of poisonous particulates instead.
The main issue is the complete lack of external controls. Where previous models had volume and mute buttons, the C520t has unceremoniously dumped them in the search for clean lines and cool design. Now this wouldn't be such a problem if the volume control was easily accessible from the map screen, but it isn't. In fact it's buried four clicks deep in a settings menu and this makes it a right royal pain in the rear end to change.
Another area where Mio has taken a step backwards is in audio quality. Compared to the C510e and other higher end sat-nav systems, the C520t's speaker is poor. It sounds harsh, scratchy, grates on your ears and you have to turn it right up to hear it properly.