Probably the number one benefit of sat nav is that it can help you cut down on your journey time - and let's face it, while we love our cars, there are usually other things we'd rather be doing. The Sony NVX-P1 is peerless in that respect, because no other satnav system on the market will save you so many hours behind the wheel. However, before you get excited, read on, and I'll explain why you'll lose hope trying to program this and thus not bother going on trips.

Due to the unit lacking a touchscreen - you're forced to arrange your route by fiddling around with the keypad in a relentless series of menus that could easily be used as an instrument of torture in banana republics. After we'd spent minutes of our lives that we'll never reclaim slaving through the interminable process of keying in letters, we were then informed that our destination - a town of nearly 150,000 people - didn't exist. Stupifying.

Then there's its size - this is a dreadnought in both dimensions and looks, and it hungrily eats windshield space like an opera singer locked in a pasta factory. But hidden among the slow loading times and irritating menus is a device that works pretty smoothly, with maps for 16 countries pre-loaded and a good, if not spectacular, display.

However, the sheer force of will you'll need to navigate it and endure the clanky robotic voice commands renders it impotent compared to other products on the market. Sat navs are meant to save time, but you may waste the saved time and more besides by using this behemoth.