This weekend I finally found some time to get a huge step further with MyTrainLog.
I removed the Database stuff completely as its delaying the application development to much. I just using plain old ObservableCollections right now with a (De)Serializer to store the stuff in IsolatedStorage when the app is loaded/unloaded/etc.
This approach seems to be rather fast - at least on the emulator. No real device in sight right now.
I reall dont know whats happening if the collections are going to grow too much. Is the RAM storage unified? Don't know yet. Maybe I need to go back to Database later on - but the infrastructure is there at least.
What I noticed in the Beta tools is - the lack of controls. The Pivor/Panoramic control is not officially there - an very essential part of my app. I am using the nice one from Codeplex.com so far. Perfectly ok. No Date/Timepicker, no SelectBox/Combobox for easy selection of options. No checked Listbox etc. Everything could be coded by hand but it would speed app design up alot with some help here if you dont need to do the plumbing code for each control.
Anyways - the controls will come some day or another and the devs will incorporate them to make the look and feel of the plattform unique. And the split between the native MS apps and the 3rd party stuff will be getting less and less important and visible.
So far I guess about 80% of my app is ready. Ok, 20% will take 200% of the time :)