I have the 340S. Pretty happy with it. We bought it for an upcoming out of state trip but have been using it around the area since summer to familiarize ourselves with it. (Actually, I picked it up so early because it was on sale at a good price.) My wife is the "navigator" so she needs to know how to use it.
It has come up with routes that we would have never considered. As far as real world driving considerations, I guess I'm not certain on that. We aren't paying for any additional available functions such as real time traffic and what not. If you're referring to the IQ Routes feature, perhaps that is what has us on less well traveled roads sometimes. Sorry to not be that "into" the device.
There is one quirk that drives me batty. We've got a North South road that stretches for probably a good 50 miles (estimate) called Telegraph Rd. For some reason the TomTom thinks that it is a series of roads strung together. There is a 6 mile or so stretch that it will just drive us batty on. It keeps telling us to get in the right lane and to get onto the same road that we are already on. Every 500 ft. it's telling us this. Suddenly it gets happy. The road is also US 24 so I think whomever coded it into the software called it by both names or something and the TomTom is doing a HAL impersonation.
I'm not sure I even answered your question.
I had borrowed a friends older TomTom to see if it was really something we wanted. The borrowed one was none too happy with route changes. If we needed to deviate from the route it prepared, it would repeatedly try to get us back on that route. With construction or traffic, that is not always an option. This unit just goes with the flow and creates a new route. Way better than the older one.