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 | evenly matched | Effectively the same output - 80W against 80W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output nearly doubles (150W and 150W). |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (100dB vs 100dB). |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | A | Only Rotel S14 has AirPlay 2 and Chromecast. |
| Analogue inputs | B | Rotel A14 MKII takes more analogue sources - 4 against 1. |
| Phono stage | depends | Rotel A14 MKII has a built-in phono stage (MM) and Rotel S14 does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| Room to grow | evenly matched | The same expansion options on both. |
| Price | B | Rotel A14 MKII costs less - $1,600 against $2,499 at list. |
| Watts per dollar | B | Rotel A14 MKII is the cheaper watt - about $20 per watt against $31. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Rotel S14 B Rotel A14 MKII
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?
Rotel A14 MKII has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If you play records, Rotel A14 MKII saves you buying a phono stage; if you do not, ignore that row entirely. Think about the whole system: the roughly $899 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
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.