I use this app in the Pacific Northwest, including the Columbia & Willamette rivers and so far Im very impressed. I dont really have much to compare it to, but the charts are very detailed and (so far) extremely accurate. The plotter page is wonderfully intuitive with easy tap-to-place waypoints and very professional speed, BRG, dist next windows. You can input your boats specs to anticipate leg-length and fuel consumption. It even has a massive search database for locating fuel and any written info on sections of your voyage. Im astonished, frankly, to be the first person to write a review here and if Id seen others, I might have actually rated it a 5.