Currently using Aukey EB-40's and music plays well with no dropouts with my 645M (controls on left side). I previously used a pair of Mee-X7 Plus earphones which had any dropouts - the controls (and I assume Bluetooth antenna were located on the right ear side. Note that the dropouts happen on outdoor runs only. When indoors, the Mee-X7 Plus headphones don't have any dropouts - walls work great in bouncing the BT signal from the 645 around.
I wear my watch on my left wrist as I am right handed and prefer to operate the watch while it is on my left wrist.
Has anyone tried the new Jaybird Vista truly wireless earbuds, outside, while wearing the watch on their left wrist? What's your experience been like? As an aside, any foam tips available yet for the Jaybird Vista? My ear canals cannot stand silicone tips - the seal is too tight with silicone - I prefer Comply foam tips.