Given your preference for hardy power and mulching capability, the Yard Force EM U44 is the better choice for your needs.
Here is a short breakdown of why:
The Winged Blade Advantage: In "hardy" environments (thick, damp, or slightly overgrown grass), the Yard Force’s winged blade is superior. It creates higher airflow, which provides better lift for a cleaner cut and significantly better mulching/collection performance compared to the standard flat blade on the VonHaus.
Proven Reliability: Since you are already familiar with the Yard Force and its durability, there is little reason to switch. Yard Force is generally regarded as a "workhorse" in the corded electric category, whereas VonHaus, while good for standard lawns, often uses more lightweight plastics that may not hold up as well in tougher conditions.
Cutting Width: The Yard Force offers a slightly wider cut (44cm vs 43cm), which, combined with the 1800W motor, makes it slightly more efficient for larger or more difficult areas.
Verdict: Stick with the Yard Force EM U44. The winged blade and its proven ability to handle tough conditions outweigh the "newer" design of the VonHaus.