Which is better for sports?

The Pro Series 75R8H5. Its 120 Hz panel keeps fast motion clearer, while the 75R8B5's 60 Hz panel can look softer during quick pans.

Is the Pro Series worth stepping up to?

Yes if you game or watch a lot of dark, high-contrast content. The Mini-LED dimming and 120 Hz refresh are the main reasons to pay more.

Which has better picture quality?

The Pro Series. Local dimming gives it deeper blacks and higher peak brightness than the edge-lit 75R8B5.

Do both run the same smart interface?

Yes. Both use Roku OS with the same app selection and voice remote, so the software experience is nearly identical.

Which is better for console gaming?

The Pro Series. It supports 120 Hz and VRR, which the 75R8B5 does not.

Both are built similarly and should last a comparable number of years. The Pro Series has more advanced hardware, but neither has a clear reliability edge.

Roku 75R8B5 75" QLED TV vs Roku Pro Series 75-Inch 4K QLED TV

Both are 75-inch 4K QLED Roku TVs, but the Pro Series (75R8H5) is the better set. Its 120 Hz panel handles sports and console gaming far better than the 60 Hz 75R8B5, and it adds Mini-LED backlighting with local dimming for deeper blacks and less blooming. The 75R8B5 is a solid budget big-screen pick with the same Roku OS and voice remote, but reviewers consistently rate the Pro Series higher for picture quality and motion.

Choose the Roku 75R8B5 if you want a large 75-inch 4K QLED screen for everyday streaming and movies and do not need 120 Hz motion or local dimming.
Choose the Roku Pro Series 75R8H5 if you watch sports, play console games, or care about contrast and brightness, since its 120 Hz panel and Mini-LED dimming are clear steps up.

Prices

Roku Pro Series 75-Inch 4K QLED TV: $999.99 at eBay (checked today)