The GD-350, like the Rangeman, are a bit "out of line" if you think of Casio's current intent for the G-Shock. Unfortunately the G-Shock turned from a TOUGH & affordable watch to a fashion statement (that's still tougher then anything out there). Nowadays it's easy to have the distinct impression that Casio wants their watches to be seen as something trendy and hip, and not a tough-as-nails tool that can outlast human kind. The GD-350 and the Rangeman are different because (though not cheap) are models made to be simple to use, tough and low profile (and I'm very aware that the GD-350-1BJF only marginally fits in this description), a watch to be worn as a "time monitoring tool".
If you add all that to a VERY nice module and a fantastically comfortable watch to wear, it's easy to see why the Vibrator is one of the Top 5.
PS: The 6900 (or at least some of them) could also be considered one of the top´ones, but it's not a current model.