In my opinion it depends on what you started out with and 'grew up' with. For me that is Windows and MapSource. Now I have used a MacBook Pro and I have used BaseCamp successfully but I just don't like them. I much prefer the hierarchical structure of Windows and MapSource since I am most familiar and comfortable with it.
Now with that being said the Garmin 590LM and the Harley version Road Tech 590LM as they come are not compatible with MapSource. However they can be made to be compatible. Garmin says they don't guarantee the results but I've made the change on my RT590 LM and on the Nuvi in my cage to use MapSource and have had absolutely no problem.
Here's what you need to do to make the 590 work with MapSource:
Thank you for contacting Garmin International.
MapSource reads devices that use Mass Storage mode. Your zumo 590 uses MTP (Media Transfer Protocol). MapSource will not read devices in this mode.
You may change the mode to Mass Storage; however, this device is not supported with MapSource. With that being said, you may attempt to use the program with the device, but if any issues occur, it will likely come down to compatibility issues, and we will not be able to do much about it.
To change the mode:
1. Turn on the zumo 590
2. Touch Volume
3. Touch and hold the upper right hand corner
4. Touch Configuration and Settings
5. Touch MTP Settings
6. Select Mass Storage
7. Touch Save
The device will now communicate to the computer in Mass Storage mode.
For additional assistance, please reply to this email or call us at 1-800-408-7419 Monday-Thursday 8am-6pm Central and Fridays 8am-5pm Central (closed holidays).
With Best Regards,
Leanne
Product Support - Automotive Team
Garmin International