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 70W 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 140W). |
| Built-in DAC | A | Both decode on board, but only Rotel A14 MKII handles MQA. |
| Streaming | evenly matched | Only Rotel A14 MKII has Roon. Neither list is longer in a way that matters - check the one service you actually pay for. |
| Analogue inputs | A | Rotel A14 MKII takes more analogue sources - 4 against 2. |
| Room to grow | evenly matched | The same expansion options on both. |
| Amplifier class | depends | Rotel A14 MKII is Class A/B and Technics SU-G700M2 Grand Class is Class D. Class A/B runs warm and is the long-established mainstream choice; 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 | Rotel A14 MKII takes up about 21% less shelf area (1642cm² against 2069cm²), and it is 100mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Rotel A14 MKII costs less - $1,600 against $2,700 at list. |
| Watts per dollar | A | Rotel A14 MKII is the cheaper watt - about $20 per watt against $39. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Rotel A14 MKII B Technics SU-G700M2 Grand Class
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 is the easier recommendation: it leads on most of the measured areas and costs less. Take Technics SU-G700M2 Grand Class if one of the "depends" rows above describes your system. Think about the whole system: the roughly $1,100 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.