When selecting an 8-ton excavator (often categorized as a midi-excavator), you must prioritize the engine brand and emission standards (e.g., Kubota, Yanmar, or Cummins for reliability). Key performance metrics include a bucket capacity of 0.3 to 0.35 m³, a maximum digging depth of approximately 4,000-4,500mm, and engine power ranging from 45kW to 55kW. Ensure the hydraulic system uses reputable main pumps (like Rexroth or Kawasaki) to guarantee smooth compound movements and durability under heavy loads.