Which is better for commuting?

The Pixel Buds Pro 2. Active noise cancellation blocks engine and crowd noise, and it lasts up to 8 hours with ANC on. The original Buds only isolates passively and runs about 5 hours.

The Pixel Buds Pro 2 by a wide margin. It gives up to 12 hours per charge and up to 48 with the case, against about 5 hours for the original Buds and no case.

Is the Pro 2 worth stepping up to?

Yes for most shoppers. You get active noise cancellation, multipoint, spatial audio, a smaller fit, and much longer battery. Step down only if you want a neckband.

Do both work with iPhones?

Both pair over Bluetooth with iOS, but the Pixel Buds Pro 2's Fast Pair and deeper Assistant features are built for Android. On iPhone you lose some of that integration.

Which fits better during workouts?

The Pixel Buds Pro 2. It is true wireless at 5.3 g per bud with three tip sizes and a secure in-ear seal. The neckband stays on but swings during running.

Can I use one earbud at a time?

On the Pixel Buds Pro 2 you can use a single bud for calls and audio. The original Buds are a connected neckband pair, so both stay with you.

Google Pixel Buds Pro 2 vs Google Pixel Buds (2017)

The Pixel Buds Pro 2 is the clear pick for most people. It adds active noise cancellation, a Tensor A1 audio chip, spatial audio, multipoint, and far longer battery life, and reviewers praise its smaller, more secure fit. The original Pixel Buds (GA01470) is a neckband design with passive isolation only, 5 hours of playtime, and no multipoint. Buy the Pro 2 unless you specifically want a neckband that hangs around your neck.

Choose the Pixel Buds Pro 2 if you want active noise cancellation, a secure in-ear fit, spatial audio, and all-day battery.
Choose the original Pixel Buds if you prefer a neckband that stays put and don't need noise cancellation.

Prices

Google Pixel Buds Pro 2: $52.82 at MirMadina (checked today)
Google Pixel Buds (2017): $156.99 at Staples (checked today)
Difference: the Google Pixel Buds Pro 2 is $104.17 cheaper than the Google Pixel Buds (2017) today