It is not common case but why not? These work fine with POILoader created POI and most of model have beeper. Usually 22 (24 with transparent border) pix is good for handhelders as for low-resolution Nuvis.
But Montana have especially got the same navigation engine like Nuvi even so a some trouble with routing is present in compare with truly automobile devices. And fact what Montana do not support Cyclops is a big lack from Garmin.

There is the one difference with Nuvi it are not speech prompts but Garmin navigation engine is perfect even without its.