I have to say that after 2.5+ hours searching for a good way to provide Google Maps on my wordpress site, GmapsMania was the only one that worked simply and well for embedding Google Maps into my wordpress installation. When you are embedding Google Maps into your wordpress post, you have to keep in mind that WP does not support iframes. I tried using the Embed Iframe plugin, but it turned out to be very picky about when and where you put the iframe code in, i.e. go to the HTML tab, enter your iframe code, make sure that you saved your page while the HTML tab was still open, then go back to the Visual tab and make sure you never opened the HTML tab again, etc. It was a nightmare.
So, GmapsMania solved the problem for me, and I have to say it is the simplest way to put Google Maps on WordPress.