I can tell only from experience we made during the time we are using this device. It wasn't only some brands, what it makes so difficultly to give a general answer. Sometimes they had problems within the same series of a brand. It happen that these cards was recognize and the next time not. Transcend, and Kingston, Scandisk I have in my mind. Sometimes they are working, sometimes not. Very often they had a problem during a trip and we didn't find a general answer, because at the same time other friends had no problems with the same card in their device. I didn't had any problems with my 32GB Lexar Class 10 (so I'm lucky), but we all have a backup-card if we made a longer trip (only in case of...). It seems these problems are solved since version 4.80.

The problem is this kind of problems and some other things makes it not easy to find good arguments for a new Garmin device in the future. If a manufacturer solves a major problem not before end of a product live-cycle and eliminate functions within a cycle like the guide issue, it will not make a future customer really happy and trust him to buy once more an expensive device. When I am looking to my friends, there are already five of them who made the decision against Garmin. And the most important argument is that they felt Garmin is not listening to the needs of bikers with their actual products for biker (all Garmin customers since very long time). They did pay a lot for this kind of premium devices and become less functionality and quality in comparison to other product lines from Garmin.

Anyway, I am quite happy not to have the need to look for a new device this year.
To say it clear, I don’t like to make here a statement pro or contra Garmin, but my feeling is that Garmin needs to listen more carefully to their customers. Only a guess...