Other weaknesses include the perennial problems of live navigation that you're relying on your mobile data connection (the reliability of this will vary, depending on your network and where you are in the country) and the Wayfinder servers staying up. To be fair, Wayfinder does attempt to circumvent this potential stumbling block by downloading blocks of mapping and caching it in the phone's memory, so you always have the some mapping data to work with. It offers those map downloads too. But if you stray off track too far and lose your data connection (I occasionally found my T-Mobile connection interrupted, even in London) you'll be stuck. It's also not going to be a realistic proposition to use the product abroad, with mobile data rates being such a rip-off, though this is not the fault of the Wayfinder product - blame your mobile operator for that.
What you can blame Wayfinder for is the cost of added extras. Where the main product is reasonably priced, the speed cameras and traffic information features are not. Live navigation software is the ideal way of transferring such data and keeping it up to date reliably - it can be downloaded at the same time as route information - but you have to pay a hefty premium if you want the privilege, with annual speed camera updates costing £28 and traffic information another £20 per year.
It's worth noting that Telmap and CoPilot Live 7 (the latter is my current phone navigation application of choice) both include free traffic information and that Telmap's rolling contract, which allows you to pay just £5 for one month of navigation and then opt out after, is much more flexible.
So for the ultimate in flexibility, traffic, European mapping and speed cameras, Wayfinder is never going to be able to compete with full-blown dedicated devices such as TomTom's excellent range of sat-navs. And it's not as good as CoPilot either.
But I think that, despite the lack of free traffic info it is - just - a better bet for live navigation than Telmap. It has more innovative features and better flexibility, and at £48 for three years of map updates, it works out far cheaper in the long run. If you want a basic navigation product that doesn't suck the storage potential out of your phone, it's the best product of that ilk I've used.