I bought a Vivosmart as a replacement to my FitBit Force earlier this fall. While the device is great and offers much more than the Force did. The Mobile and Web interface are inferior products.
I'm going to leave the MFP issues aside because who knows who's to blame with the synch failures.
I didn't have near the number of device synch issues that I am having with the Vivosmart.
Four times in the past 2 weeks I've had to delete the app and re-install to make it work.
Also, FitBit allowed me to create a workout much easier than in Garmin. And it had functionality that kept the device from double counting step and calories burn.
This is something that would be great in Garmin Connect.
FitBit also had an internal calorie/food diary. While many people are loyal to MFP, an internal calorie / food diary eliminates moving parts and keeps everything in the same universe.
Last night, I DL'd the new Under Armour Record app, The functionality relies on a connection to Garmin Connect but the navigation looks similiar to MFP.