Epson - WorkForce Pro WF-7840 vs HP - OfficeJet Pro 9135e

These two are nearly even on the Mars Score (73.1 vs 71.2). The decision is not about overall quality — both clear the bar — it is about which specific trade-offs fit your use.

Pick the WorkForce Pro WF-7840 if you care most about pages/min (mono). The biggest gaps in its favor are pages/min (mono). The single most decisive one: Pages/min (mono) — 13.64% more. 25 vs 22.

Pick the OfficeJet Pro 9135e if you care most about pages/min (color). Its strongest claims are pages/min (color). The single most decisive one: Pages/min (color) — 50.00% more. 18 vs 12.

Both ship with comparable type, color, auto duplex, so those specs do not separate the two — focus on the differences below.

Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.