So far the camera part seems pretty easy. The 6D is similar enough to my 5D (first generation). The on/off switch is in a different place and due to the auto sensor cleaning, the camera starts up from totally being "off" a bit slower. The menus are laid out slightly differently but are still easy to navigate, especially compared to the average compact point and shoot. The 6D focuses noticeably faster on the center point though and the quiet mode of the shutter is appreciated and is already my default setting. The GPS is not as good at obtaining/retaining lock as I would have hoped, but I'm sure it will work fine for most of what I'm interested in. I also think the GPS contributes to the very limited battery life (compared to my 5D). I've yet to mess with the video (or live-view option) and I haven't (and I doubt I ever will) use the WIFI. As a data point, I don't believe I ever once have used the Eye Control Focus on my EOS 3.
Lightroom is very different from Photoshop CS version whatever. It is a totally different thought process and it really serves a different function. I just wanted a reasonably priced raw converter. Photoshop is just far too expensive. CS6, the current version, doesn't do anything that I care enough about that my CS4 doesn't do, and it's not available for Linux, which is where I'm eventually headed. So far I've figured out how to do adjustments such as curves etc. and spit the result out as a jpg. I'm either going to need a book or have to take a class to get beyond that and to get the benefits of the program. I'm pretty sure that I don't think or see the world the way Lightroom does so the organization advantages that it probably shines at for photography are lost on me. I generally don't like organization, putting things in boxes feels like it limits the possibilities and certainly tends to keep me thinking in boxes. As I told someone at work once, "If I don't put things in boxes, it is much easier to think outside the box".
The GPS. I'm sure (at least I sure hope so) that there are all kinds of cool things that can be done with the GPS function. I've not even scratched the surface due to lack of time. I do know how to turn it on/off, set up logging. Just tonight, I put the photos below in the Canon supplied Map Utility. Eventually I'd like to do a little map or Google Earth type thing of walks or hikes I do with my camera so that you can click on points along the way and see the photo from that point. It probably isn't hard, I just need to learn how to put it all together.
In the meantime, below is a screen capture of the Map Utility with the photos locations marked, and then three of the photos themselves from my walk around Patuxent Research Refuge a couple days ago.