One is a streaming all-in-one and the other is an amplifier. Judge them on how many boxes you want and what you already own, not on the spec sheet alone.
| Area | Better | Why |
|---|
| Power | A | HiFi Rose RA280 has more power - 250W against 150W into 8 ohms. That is about 2.2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Grip on hard loads | B | Cambridge Audio Evo 150 holds up better into a 4-ohm load: its output increases strongly to 250W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | B | Cambridge Audio Evo 150 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Streaming | B | Only Cambridge Audio Evo 150 has AirPlay 2 and Roon. |
| Room to grow | B | Only Cambridge Audio Evo 150 offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Headphones | depends | Only Cambridge Audio Evo 150 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | HiFi Rose RA280 is Class AD and Cambridge Audio Evo 150 is Class D. Class D runs cool and draws almost nothing at idle. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Cambridge Audio Evo 150 takes up about 27% less shelf area (1190cm² against 1638cm²). |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | A | HiFi Rose RA280 is the cheaper watt - about $14 per watt against $22. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A HiFi Rose RA280 B Cambridge Audio Evo 150
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both amplifiers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Cambridge Audio Evo 150 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Cambridge Audio Evo 150 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. Start with the room. In a large or open-plan room, or with speakers that are hard to drive - low sensitivity, or an impedance that dips - HiFi Rose RA280 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 150 watts is already more than most people ever use, and the extra 100 watts would be headroom you pay for and never hear.
What a spec sheet cannot show: how either sounds with your speakers, how the controls feel day to day, and what the app is like to live with - which is where most all-in-one amplifiers are actually won or lost. Power figures are the manufacturers' own and are not measured to a common standard, so treat small differences as noise. If you can hear both, that will tell you more than any row above.