I'm a diehard Kobo/top hat fan.
If you haven't used an ereader screen in a glider, you are in for a treat.

I just replaced my first kobo (left other in rental car )
and my new (old stock) kobo has the sunlight issue. It's becoming very light during the flight to almost unreadable. This is especially bad with high temperatures. I did not have this problem with my previous kobo so I think this is a QC issue.

I have my kobo wired (soldered) to a colibri II. This is an amazing setup that gives you everything you need from a moving map + IGC approval for badge/comp/record flying. The kobo charges the colibri and the whole unit is charged from a micro USB.

I have noticed the radio inference if I hold this unit close to my Dittel radio, doesn't effect it unless I hold it close though so it's a non issue for the most part.