Greenworks 40V 21" Brushless Cordless (S vs Electric Lawn Mower, Self-propelled Lawn

Quick Verdict

The Greenworks 40V 21" Brushless Cordless Self-Propelled Lawn Mower is the clear winner for most homeowners. It offers a better balance of power, reliability, and user satisfaction at a reasonable price. The alternative 40V (2x20V) 18" self-propelled mower is a budget-friendly option but falls short in cut width, battery system efficiency, and overall performance.

Side-by-Side

Where Greenworks Wins

Greenworks dominates in three key areas. First, the 21-inch cut width is a meaningful advantage—it covers 17% more grass per pass than the 18-inch alternative, reducing mowing time and passes needed. Second, the brushless motor is more efficient and durable than a brushed motor, delivering longer runtime per charge and less maintenance over time. Third, the single 40V battery system is simpler and more reliable than the dual 20V batteries in series; fewer connection points mean fewer potential failures, and you can use the same battery with other Greenworks 40V tools.

The higher user rating (4.1 vs. 3.7) and larger review count (1,527 vs. 228) indicate proven satisfaction and reliability in the field. For $50 more, you get a mower that is better built, faster to use, and backed by a stronger reputation.

Where the Alternative Wins

The alternative’s primary advantage is price—it costs $50 less. For shoppers on a strict budget, that difference matters. However, the savings come with trade-offs: a smaller 18-inch deck means more passes, a less efficient brushed motor, and a dual-battery system that can be less convenient (you must keep two batteries charged and matched). The 3.7 rating suggests mixed user experiences, likely due to lower build quality or inconsistent performance. This mower is best suited for very small, flat lawns under 1/4 acre where the smaller deck and lower power are less noticeable.

Which Should You Buy

Choose the Greenworks 40V 21" Brushless Self-Propelled if you have a lawn up to 1/3 acre, want faster mowing, and value long-term reliability. The brushless motor, larger deck, and proven user satisfaction justify the extra $50. It’s the better investment for most yards.

Choose the alternative 40V (2x20V) 18" mower only if your budget is tight and your lawn is under 1/4 acre, flat, and simple. Be prepared for a slower mowing experience and potentially shorter lifespan due to the brushed motor and dual-battery setup.

For the vast majority of homeowners, the Greenworks mower is the smarter choice—it wins on performance, efficiency, and user trust.