Hi BITOG, I have the high-wheel version of the following (Amazon link) Yard Machines push mower with the 6.5HP 190CC "Quantum" style engine. I'm not sure if this mower's engine is truly part of the "Quantum" lineup, but that's certainly what it resembles. It has served me flawlessly for, gosh, at least 12 years without skipping a beat. Immediately following the first mow of every year, I extract all of the oil with a Pela 6000, pour in 18.5 oz of fresh Briggs & Stratton SAE 30 oil, change the spark plug with a new OEM Briggs & Stratton plug, and change the air filter with a new OEM Briggs & Stratton air filter. The only gas that ever goes into the engine is fresh 88 octane top-tier gasoline mixed with the appropriate amount of Sta-bil and kept in a self-sealing "No-Spill" brand gas can to keep gasoline vapors out of our atmosphere and keep as much humidity as possible away from the ethanol in the gasoline. People wonder why their mowers stop running every couple of years while my old, basic mower keeps on chugging...taking care of a mower is not that hard. https://www.amazon.com/yard-machines-21-inch-powered-11a-439r729/dp/b0013mwgre?tag=indifash06-20 But, all of that is irrelevant; I just thought you all here might find the maintenance bit interesting. I'm actually here because I'm throwing around the idea of getting the following Yard Machines mower from Home Depot, which appears to be the evolution of my current mower, just to mix things up a bit. The new OHV Briggs & Stratton engines intrigue me and I would like to give one a try. Plus, If I manage to spare some fuel consumption and therefore some CO2 output (even a small amount), that's better for all of us. The only thing that concerns me about the new mower is that it has a smaller 140CC 550EX engine, which I hope would not feel underpowered compared to my current 190CC Yard Machines, despite the bump in power output per unit displacement with the newer OHV engines. http://www.homedepot.com/p/Yard-Machines...BE729/204686133 I mulch my fescue lawn almost exclusively and usually my current mower is up to the task. However, the old thing seems to be getting a bit tired and sometimes bogs to a speed less than ideal for mulching when I take too big a bite. It still gets the job done, though, and I'm satisfied with its performance. For those of you who have experience with both the 190CC 6.5HP and the 550EX, do you think I would notice a big difference in power between the two engines? If not, great. Otherwise, I might look at mowers with the 625EX, 675EXi, or 725EXi. Thanks!