One of the truly committed and trusted people in the industry are The New Wheel in San Francisco.
They recently reviewed Integrale S11.
They also S&*%t ton of ST2's to the tech savvy bay area people.
Having owned an ST2 for sometime, I can share a few things.
It's a great bike with wonderful range and speed. It's also heavy and may not be as agile as S11. For short distances, I prefer my NEO Nitro because it feels agile. But for long distances > 20 miles, ST2 is great fun. They can improve the racks and some of the drive components.
Personally, for commuting purpose, I wouldn't get a mid-drive of Bosch or Impulse. Not because of quality issues, but just because mid-drives don't over exert and harder to maintain speed. I personally believe mid-drives are meant for off-roading and low speed applications.
Let us know what you end up with.