A generation apart: Monitor Audio W1M E is the newer design, against a 2016 model. Newer is not automatically better, but the older one is more likely to be discounted or near run-out.
| Area | Better | Why |
|---|
| Bass | B | Definitive DI 5.5LCR digs deeper - 28Hz against 40Hz. |
| Amplifier needs | B | Definitive DI 5.5LCR is more sensitive (89dB vs 84dB), so it goes louder on the same amplifier. |
| Size | depends | Definitive DI 5.5LCR is easier to place; Monitor Audio W1M E is bigger, which usually goes with fuller bass. Your room decides. |
| Price | evenly matched | Much the same money ($998 vs $998 a pair). |
A Monitor Audio W1M E B Definitive DI 5.5LCR
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 speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Definitive DI 5.5LCR has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 40Hz anyway, so judge these on the other rows instead. In a large or open-plan room, Monitor Audio W1M E has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Definitive DI 5.5LCR is the easier speaker to get right.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.