What are the joys of Garmins?

I use the garmin 800 & 500, i originally bought the 500 before getting the 800 as i started to do long distance riding.
The main advantage i found using the garmin that it will warn you if go off course instead of a few miles down the road before you realise that you have gone down the wrong road.
The other advantage off the 800 is that you can use an external power pack to run it.
I have a stem bag that i use when i need it.
I use the 500 for more data reading as i found that there is a slight discrepancy between them.
The 800 will give you 11-12 hours on low brightness and the 500 will give you around 15 hours on low brightness.
I have found that using garmin connect to map routes can corrupt the route when transfered to the 800, so i tend to use RWGPS for mapping routes, also i find it easier to use and can download other peoples routes.