The "Navman S Sat Nav" series range from the S30 entry level Sat. Nav. to the high end S90i Sat. Nav.
I'll try to point out some of the differences between the various models.
The S30 is a very nice entry level model that is not bad value at under £130. It's a good model for regular day to day use - (by families for example). It is straight forward to use, the verbal instructions are clear and precise and it comes with maps of Ireland and the UK
The S70 (£165) has a few more feature than the S30 - some of the main ones being that the screen is slightly larger, it has Western European maps and it has bluetooth. It is a useful model for people who regularly visit the continent - or who drive for a living.
The S90i (£235) is the high end model in the range and a lot of reviews have questioned whether the cost is worth it. It does come with a lifetime subscription to real-time traffic information and "voice to text" which can read out the road and place names as well as giving instructions. It's very good - but I'm not personally convinced it's good value.
Finally it is worth mentioning that the Navman series use TeleAtlas to provide the maps for their SatNavs. Some people are critical of TeleAtlas and argue that Navteq provide better maps, but in fairness there are just as many people that argue that TeleAtlas maps are better. My conclusion is there are some small flaws in both sets of maps and people's opinions are shaped by whichever system has let them down.
Higher end models in this range (the S70 and S90) have the NavPix- navigate to pictures feature - which is very clever - but I think that whether you like it or not depends somewhat on whether you regard your SatNav as a tool to do a job - or whether you like your gadgets to be clever.
Hope this was useful. Some of the reviews at Amazon do make interesting reading.
Here is their advert.
and here is another one.
