I have the 740s. I think 4-5 other boats in our marina have them now, too. I've had half a season to play with it. Nice unit, very good value. In fact, it was a 2nd power cable and bail mount that I ordered for it that are backordered. I'm going to wire it up at my lower helm so I can use it at either station. Saves having to buy a whole separate unit for those rare occasions I run from below.
I got the radar package, but not the sounder transducer (yet). The radar is pretty good for a small (in power and display size) unit. One small issue with the radar overlay; the yellow blips blend in with the background too much. But then again, I've never looked into whether or not I can change the color. And I have the satellite image background turned on too, which makes it worse.
Screen navigation is easy and intuitive, the screen refresh is snappy, and it's visible in the sun, although sometimes I have to take my sunglasses off. Transferring waypoints and (maybe someday) firmware upgrades via SD card is simple.
I haven't yet created any routes on the fly, that's usually a challenge with any of these units. The automatic routing worked great most of the times I tried it, but one time it plotted a route going the wrong way until it ran up on shore, then backed up and went around the land in question much too far offshore. So some common sense will still be required to use that feature.
West Marine only price matches brick-and-mortar stores in their area, not online pricing. Still, that's where I bought mine. Same price as any on-line places I found at the time. The guy who sold it to me said their margin on electronics is very small.