I have a Nuvi 205w with the ’09 Lakemaster chip in it. Works great. The only limitations I see are specific to the 205 itself, it’s a little old so the software functionality isn’t as good as some newer models and of course a bigger screen would always be nice. Otherwise I’ve been happy with the setup.
The Garmin version of LakeMaster will work in nuvis. You must turn off the built in map, City Navigator. The background map on the LakeMaster card is City Navigator so you won’t have to change back unless you leave the geographic area of the map card.
I have a lakemaster chip i use with my garmin nuvi 500 (i think that’s the model). the idea was to use it soft and hard water. I don’t recomend it for in the boat because the screen is pretty small, ice fishing it works pretty good.