Which is better for marathon training?

The Powerbeats Pro 2. Its earhooks stay put over long runs and its battery lasts far longer between charges. The Momentum Sport wins only if you want temperature data during the session.

Which has better water protection?

The Momentum Sport, at IP55 versus IPX4. It resists dust and stronger water jets, so it handles heavy sweat and rain better.

Does the Powerbeats Pro 2 work with Android?

Yes. It pairs over Bluetooth and the core features work, but Spatial Audio with head tracking and some H2 features are limited to Apple devices.

Is the Momentum Sport worth stepping up to?

Only for the biometrics. Body temperature and Polar integration are genuinely useful for structured training. Otherwise the Powerbeats Pro 2 gives more battery, a more secure fit and stronger owner ratings.

The Powerbeats Pro 2 by a wide margin: up to 10 hours per bud and 45 with the case, against 6 and 24 for the Momentum Sport.

Which is better for calls?

The Powerbeats Pro 2. Owners consistently praise its microphone and call clarity; the Momentum Sport has far fewer user reports to judge from.

Beats Powerbeats Pro 2 vs Sennheiser Momentum Sport

Buy the Powerbeats Pro 2 for most athletes: the earhooks stay locked in, battery runs far longer, and ANC is proven on gym noise. The Momentum Sport is the pick only if you want body-temperature tracking and Polar integration and can live with shorter battery life and a smaller review base. Owners rate the Powerbeats higher, and its Apple H2 chip gives smoother pairing on iPhone.

Choose the Powerbeats Pro 2 if you want secure earhooks, long battery life and reliable ANC for training.
Choose the Momentum Sport if body-temperature sensing and Polar or Strava integration matter more than battery life.

Prices

Beats Powerbeats Pro 2: $17.99 at Rent-A-Center (checked today)
Sennheiser Momentum Sport: $117.72 at Amazon (last seen Nov 9)
Difference: the Beats Powerbeats Pro 2 is $99.73 cheaper than the Sennheiser Momentum Sport at the latest prices (Nov 9 and Nov 10)