I have a Magellan Crossover and a Baja540. The Magellan is MUCH more user friendly, though there is still a learning curve. The majority of trails I have been on have been on the preloaded Magellan map, but the topo detail is not great. The Magellan software is pretty bad, and it's tedious to enter in waypoints for route planning. It's also hard to navigate to those waypoints in OffRoad mode. You have to select each waypoint in turn, it will not automatically move on to the next one (or I haven't figured out how). It does sync fairly well and has a very good antenna strength. The built in battery lasts about 6 hours, and it's easily portable for goecaching. Oddly, it will sometimes lock up in Offroad mode but never in Onroad mode. It's not perfect, but it's not bad.
The Baja540 is an extremely capable, frustrating unit. It was designed over a decade ago, and the user interface, lightyears ahead of it's time back then, it's extremely dated now. Hard core users call it "that infernal machine". It does somethings fantastic, like follow tracks stored in memory, such as what the SCORE racing guys do. It has an amazing display, and it's highly configurable to display all sorts of information, in whatever location and size you want right overtop the map without losing the map in the background. Because my Jeep tires are significantly oversized, I use a large format readout of current ground speed as my speedo, and it works great. I also love the BRIGHT, dim, and keep-your-night-vision-dim display settings.
However, it's very finicky in what data you can load. To the best of my knowledge, you need to buy preloaded SD cards, or can ONLY use the propietary MapCreate software ($100). I think the machine can only read basemap files up to 450MB. A map of the southwest with only off road oriented points of interest spanning CA, NV, AZ and UT is 900mb, and it won't run. You have to break the files down into smaller chunks. Which is a bummer, because you are limited to a grand total of 5 SD cards for the life of the unit, and it tracks that through a mandatory Lowrance card reader ($50) that is slow (USB 1.0 I think?).
The MapCreate software is even worse that Magellan's software, and has to be manually patched if you want it to run properly on Vista, and it's a administrative rights only process.
I think the software and GUI from Lowrance is designed to piss you off and prevent easy use.
However, I recently learned that Lowrance has a new software utility (free download?) that can translate universal GPX files in the Lowrance format (ULR?) that can saved to a SD card on an non-proprietary reader and loaded (less than 450mb) into the Baja540 unit. I've not tested this, but it sounds great if it works.
Going with a Garmin would have been TONS easier, EVERYONE has software and maps for it, and there are tons of trails uploaded to the internet freely downloable without any headaches.
I am hoping someone like TomTom, with great customer support will build something like the Baja540, but with an interface designed by Steve Jobs at Apple, with standard batteries, standard memory card interface, Mac/PC compatible software with features of adding waypoints and building routes so easy it's almost fun! The market is wide open for such a device. If I had any money, I would build one and market it myself.
That's my dream....