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String Trimmers · Head-to-head

EGO Power+ ST1521S 15-Inch String vs Greenworks 40V 12-Inch Cordless String

Both made our Best String Trimmers for Edging shortlist, at #1 and #3. Here's how they differ and who each one suits.

Quick verdict

Choose the EGO Power+ ST1521S 15-Inch String Trimmer if you want pivoting head locks cleanly into edging position without extra tools. Choose the Greenworks 40V 12-Inch Cordless String Trimmer if you'd rather have handles moderate weeds and overgrown grass reasonably well for the price. Overall we rank the EGO Power+ ST1521S 15-Inch String Trimmer higher: #1 versus #3 in our Best String Trimmers for Edging list.

Winner overall: EGO Power+ ST1521S 15-Inch String Trimmer

Side by side

EGO Power+ ST1521S 15-Inch String Trimmer vs Greenworks 40V 12-Inch Cordless String Trimmer compared

Every difference that matters, in one table.

EGO Power+ ST1521S 15-Inch String Trimmer versus Greenworks 40V 12-Inch Cordless String Trimmer
Attribute
EGO Power+ ST1521S 15-Inch String Trimmer product photo
EGO Power+ ST1521S 15-Inch String TrimmerCheck price
Greenworks 40V 12-Inch Cordless String Trimmer product photo
Greenworks 40V 12-Inch Cordless String TrimmerCheck price
Our ranking#1 of 5 in Best String Trimmers for Edging#3 of 5 in Best String Trimmers for Edging
Pick label
BrandEGOGreenworks
Key features15-inch cutting swath with POWERLOAD auto-feed line; 56V ARC Lithium battery, 2.5Ah included; Carbon fiber split shaft12-inch cutting swath; 40V lithium battery, 2.0Ah included; Dual line auto-feed
Biggest strengthPivoting head locks cleanly into edging position without extra toolsHandles moderate weeds and overgrown grass reasonably well for the price
Main trade-off56V battery and charger add cost versus 40V competitors2.0Ah battery bogs down noticeably faster than 4.0Ah or larger packs in dense material
Best foredgingthick weeds
Decide

Which should you buy?

EGO Power+ ST1521S 15-Inch String Trimmer

#1 pick

Choose the EGO Power+ ST1521S 15-Inch String Trimmer if…

  • Pivoting head locks cleanly into edging position without extra tools
  • POWERLOAD auto-feed threads new line in seconds, useful after a long edging session wears the line down
  • 56V battery has enough torque to run the line against curb edges without bogging

Best for: edging

Prefer the alternative? See the Greenworks 40V 12-Inch Cordless String Trimmer section.

Check price on AmazonFull details
Greenworks 40V 12-Inch Cordless String Trimmer

#3 pick

Choose the Greenworks 40V 12-Inch Cordless String Trimmer if…

  • Handles moderate weeds and overgrown grass reasonably well for the price
  • Variable speed trigger lets you dial up power only when needed, saving battery
  • 3-year warranty is longer than most trimmers at this price point

Best for: thick weeds

Prefer the alternative? See the EGO Power+ ST1521S 15-Inch String Trimmer section.

Check price on AmazonFull details
The trade-offs

Pros and cons of each

EGO Power+ ST1521S 15-Inch String Trimmer

Pros

  • Pivoting head locks cleanly into edging position without extra tools
  • POWERLOAD auto-feed threads new line in seconds, useful after a long edging session wears the line down
  • 56V battery has enough torque to run the line against curb edges without bogging
  • Carbon fiber shaft keeps the tool light for one-handed edging control

Cons

  • 56V battery and charger add cost versus 40V competitors
  • Proprietary EGO battery doesn't cross over to other brands
  • No built-in guide wheel, so depth control is by feel

Greenworks 40V 12-Inch Cordless String Trimmer

Pros

  • Handles moderate weeds and overgrown grass reasonably well for the price
  • Variable speed trigger lets you dial up power only when needed, saving battery
  • 3-year warranty is longer than most trimmers at this price point

Cons

  • 2.0Ah battery bogs down noticeably faster than 4.0Ah or larger packs in dense material
  • 12-inch swath and narrower line struggle with truly woody stems
  • Not a realistic substitute for a gas trimmer on genuinely overgrown lots
Answers

EGO Power+ ST1521S 15-Inch String Trimmer vs Greenworks 40V 12-Inch Cordless String Trimmer: common questions

Which is better, the EGO Power+ ST1521S 15-Inch String Trimmer or the Greenworks 40V 12-Inch Cordless String Trimmer?

Choose the EGO Power+ ST1521S 15-Inch String Trimmer if you want pivoting head locks cleanly into edging position without extra tools. Choose the Greenworks 40V 12-Inch Cordless String Trimmer if you'd rather have handles moderate weeds and overgrown grass reasonably well for the price. Overall we rank the EGO Power+ ST1521S 15-Inch String Trimmer higher: #1 versus #3 in our Best String Trimmers for Edging list.

What is the difference between the EGO Power+ ST1521S 15-Inch String Trimmer and the Greenworks 40V 12-Inch Cordless String Trimmer?

The EGO Power+ ST1521S 15-Inch String Trimmer stands out because pivoting head locks cleanly into edging position without extra tools, while the Greenworks 40V 12-Inch Cordless String Trimmer stands out because handles moderate weeds and overgrown grass reasonably well for the price. The trade-offs differ too: the EGO Power+ ST1521S 15-Inch String Trimmer's main caveat is that 56V battery and charger add cost versus 40V competitors, and the Greenworks 40V 12-Inch Cordless String Trimmer's is that 2.0Ah battery bogs down noticeably faster than 4.0Ah or larger packs in dense material.

Is the EGO Power+ ST1521S 15-Inch String Trimmer worth it over the Greenworks 40V 12-Inch Cordless String Trimmer?

For most buyers, yes: it's our #1 pick. Consider the Greenworks 40V 12-Inch Cordless String Trimmer instead if 56V battery and charger add cost versus 40V competitors is a deal-breaker for you.

Who should buy the Greenworks 40V 12-Inch Cordless String Trimmer instead of the EGO Power+ ST1521S 15-Inch String Trimmer?

The Greenworks 40V 12-Inch Cordless String Trimmer suits thick weeds, while the EGO Power+ ST1521S 15-Inch String Trimmer is best for edging.

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