For those that have went from the Kestrel 4500 AB to the 5700 Elite AB

Depends on what you are trying to accomplish. The solver isn't very different. Just more integration, the use of apps, easier to load profiles on, and will probably be connected to more devices in the future. Also the library is always up to date on the app now thanks to AB Connect™.
 
For me, yes, absolutely. The ease of updating software and using the app to manage profiles was worth the price of admission. The 5700's compass has been more stable and the 5700 seems much more durable. Like Doc says tho, the solutions are just the same.