Between the two, TomTom Via 135 is considered to be better than TomTom Via 1505 M probably because this comes with a lot of other features that TomTom Via 135 does not have. The TomTom Via 1505 comes with a route optimizer.
It will also allow multi-route capabilities which can make connecting so much easier. There are also a lot of people who like the fact that this comes with voice commands that can definitely be very helpful for a lot of people who would like their commands to be done instantly.
The favorites menu will help you access what you are searching for immediately.