These are not the same size of amplifier: Cambridge Audio Edge M has roughly 2.9x the power of Cambridge Audio MXW70. That is about 4.6dB, so it is a question of room size and how hard your speakers are to drive, not of one being the better amplifier.
| Area | Better | Why |
|---|
| Power | A | Cambridge Audio Edge M has more power - 200W against 70W into 8 ohms. That is about 4.6dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Analogue inputs | B | Cambridge Audio MXW70 takes more analogue sources - 2 against 1. |
| Amplifier class | depends | Cambridge Audio Edge M is Class XA and Cambridge Audio MXW70 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. |
A Cambridge Audio Edge M B Cambridge Audio MXW70
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and the speakers you already own settle it. 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 - Cambridge Audio Edge M has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 70 watts is already more than most people ever use, and the extra 130 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.