Sorry about the long delay Renaud, I just got back. I have been using the Dakota just about daily and with the knowing that Garmin will take forever to address this hardware wise, I would go look at the screen brightness in the store and see if you can live with it. There is definitely a difference in brightness with the power cord plugged in the lighter.It's actually decent, I have tried all sorts of batteries with the same resolution. I am not sure if there is a software fix for this or what. I was wanting to try a experiment one day and simulate the power at the plug in with 2 AA's to see if it is software or driving higher voltages at the plug. All in all, I actually like it now better than my HCX due to how small and the touchscreen has really been nice to move the map around and the bigger screen as well. For the capabilities it has once you get use to it, it really is a great unit despite a few small issues, like the screen brightness and alarm loudness are my biggest issues. I would definitely check it out in the stores and if you like it, buy it.
Advantages
1. Very Very Small size
2. Awesome battery life (can be ran 100% off of solar with no batteries in the unit)I can get 4 days off of the batteries back and forth to work and running around.
3. Can hold 3 micro SD cards (Up to 8 gig capacity per card) in the battery compartment.
4. Holds a lot of maps and can use road,topos,street and marine maps and they route.
5. Waterproof
6. Fast Processor and fix
I like mine, I would definitely buy another one looking back.