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 | Technics SU-G700M2 Grand Class has more power - 70W against 40W into 8 ohms. That is about 2.4dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Technics SU-G700M2 Grand Class the better fit for a mid-size room, a large room and a very large room, and Naim Uniti Atom for desk or near-field listening and a small room. Match the amplifier to the room you actually have, not the one you want. |
| Built-in DAC | B | Both decode on board, but only Naim Uniti Atom handles DSD. |
| Streaming | B | Only Naim Uniti Atom has Chromecast and Roon. |
| Analogue inputs | A | Technics SU-G700M2 Grand Class takes more analogue sources - 2 against 1. |
| Phono stage | depends | Technics SU-G700M2 Grand Class has a built-in phono stage (MM,MC) and Naim Uniti Atom 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. |
| Amplifier class | depends | Technics SU-G700M2 Grand Class is Class D and Naim Uniti Atom is Class A/B. Class D runs cool and draws almost nothing at idle; Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Naim Uniti Atom takes up about 62% less shelf area (781cm² against 2069cm²), and it is 164mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Technics SU-G700M2 Grand Class costs less - $2,700 against $3,799 at list. |
| Watts per dollar | A | Technics SU-G700M2 Grand Class is the cheaper watt - about $39 per watt against $95. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Technics SU-G700M2 Grand Class B Naim Uniti Atom
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?
Technics SU-G700M2 Grand Class has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. 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 - Technics SU-G700M2 Grand Class has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 40 watts is already more than most people ever use, and the extra 30 watts would be headroom you pay for and never hear - we rate Technics SU-G700M2 Grand Class poorly for near-field use for exactly that reason. If you play records, Technics SU-G700M2 Grand Class saves you buying a phono stage; if you do not, ignore that row entirely.
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.