(ex Pebbler here) Pebble had - I believe - the most stable Bluetooth stack out there. This was due to two things:
1. Extremely talented Bluetooth engineers. Chris and Martijn were second to none.
2. Very good diagnostics tools built in house. When a user complained of connectivity issues, we could take a snapshot of the state of their Bluetooth stack. This gave us amazing insights into what was going wrong- more often than not we found that iOS and Android were doing something unexpected (we had lots of workarounds for their bugs).
FWIW a few of us went on to start a company to build more of those hardware debug tools: Memfault (W19).
1. Extremely talented Bluetooth engineers. Chris and Martijn were second to none.
2. Very good diagnostics tools built in house. When a user complained of connectivity issues, we could take a snapshot of the state of their Bluetooth stack. This gave us amazing insights into what was going wrong- more often than not we found that iOS and Android were doing something unexpected (we had lots of workarounds for their bugs). FWIW a few of us went on to start a company to build more of those hardware debug tools: Memfault (W19).