I have Reefmaster software and make my own maps. It's nice cause I fish a lot of lakes under 100 acres and most of those are either not mapped or were mapped a long time ago and are not very accurate. I have a Humminbird ( 998HD SI ) and the only problem with Reefmaster vs. the Humminbird products is I don't get some minor features like 'follow the contour' (which isn't very accurate anyhow and can be done with reefmaster maps if I set up a route and follow that). The maps are also not all pretty with background color, ( if I had a lowrance they would be but Humminbird won't make the code license available to do that), but they show contour lines and that is what I'm after.
I will say Reefmaster isn't super user friendly, so some computer knowledge is helpful. Their tech support is top notch, however.