I will start by saying that I am not an expert in GPS technology nor map building but I have used a Garmin 60cx quite a lot for mapping and data collection in my job. The 810 was a bit of a departure from what I had expected from a Garmin product given the advances in the GPS world and mobile devices in general. My current tech standard is the iPhone: You turn it on and it works.
I received my Garmin 810 as a Christmas present and was very excited to get it on the bike. I was exceptionally disappointed in my early experiences. Pretty much everything in that first couple of months was not a good experience: Getting Garmin Connect on my computer, downloading base layer maps from Garmin, updating Firmware, syncing with my iphone, Live Track not working, route building was cumbersome, the unit wouldn't follow a route, etc... Bad experience with almost no help from Garmin Tech support "oh, yeah, we are having issues with downloading...we are working to resolve that...we are hoping to have that fixed in the near future..." I would have returned it if my girlfriend hadn't gone above and beyond with that as a gift. I had resigned myself to just using it to track my training rides like I had been doing for free with Endomondo. Then...
Garmin must have fixed something with recent firmware and software updates. Combine the updates with my upgrade from my trusty iPhone 4 to a 5S and magically everything seems to be working much better! Syncing and Live Track have been working as advertised!! Route following seems to be better on routes generated through tracking on the bike but I haven't yet given the unit another shot at following a route I built on Garmin Connect.
I still have a couple of complaints: Nothing intuitive about merging the mini-SD card with the 810's internal memory and route building on the Garmin Connect site is not point-to-point navigation friendly. That last issue will be very important as I continue planning for a tour next year. It would be great if Garmin would integrate some of the mapping features that Google allows like dragging the route to another road or trail option. It may be operator error but I have played around with the routing and it just doesn't seem to be simple nor intuitive.
So, more to the point of your thread, I haven't experienced the crashing you described but plenty of other issues. Garmin is the defacto world leader in GPS devices and they have a cycling team yet the 810 comes to market with all of these challenges. I still believe in Garmin as a company but maybe they should find a way to hire someone from Apple to run their device / integration division...
My apologies for rambling. If anyone out there has suggestions for me on the route building I'm all ears...or eyes I guess.