The Toro instructions that came with my mower cite 5 hours for the initial "new mower" operation period before the first oil change and recommended 25 hours thereafter between oil changes. This is especially important with the engine design using aluminum piston and cylinder found in many mowers and importantly the case in this model as designed. My 2009 Toro Recycler with the Briggs Engine made it important to be sure the engine has no overheating or overloading episode in the first 5 hours. My instruction manual was not clear on the importance of NOT abusing the engine in these first five hours of operation. Low engine ratings by other owners in reviews are likely to occur when new owner faces the first cutting with his new mower on high and/or wet grass on the first use of the Toro after taking is home (maybe the owner has been without a working mower for several weeks before buying at Home Depot). The 5 hours should be operation that does not overheat or overload the engine because these initial hours are important "break-in" for the engine and initial operation that overheats the engine or stops it by and overload like clogging with wet grass is abuse that at this time can leave permanent engine damage resulting in reduced engine compression (because the cylinders become scratched or "scored" harming the necessary pressure seal that can then be) hurting performance, making starting difficult, and multiple hard hot shutdowns from overload can permanently make the engine problems reported in bad reviews. I was very careful to operate mine in dry grass with deck set to the highest cutting height allowing then engine to run at maximum engine speed without "bogging down" in the first 5 hours. It has been easy to start and a powerful performer since!
The Personal Pace self propel is a great feature I find to be well engineered. Better than any other mower I have used, this feature works well on my mower because it is designed to be "fail-safe". This means abuse by the owner (such as hitting a obstacle that stops the mower progress) should cause the least expensive damage to the drive (or ideally no damage at all). The rear wheels are designed to "slip" before damage to the gear teeth inside (that are plastic to allow them to fail if overloaded - if damaged by external lockup or internal gears being stripped by the axle drive gear, wheels are replaceable with least labor and Toro part cost of about $24). The rear axle has pinion gears of steel that drive each rear wheel that should not be damaged by abuse. The axle is driven by a pulley and gearbox that is stronger and protected by the failure of wheel gear or slippage of rear wheels. The axle (includes the transmission driven by the belt) has a Toro part cost of over $100 and if needing replacement costs much more when including the labor to replace. If my mower begins to lack power while climbing a hill, I adjust the cable as shown in the instruction manual to be sure the drive engages and turns the rear wheels while over adjusting can make it resist pulling the mower backward without releasing the drive properly.
Finally, I avoid starting problems caused by carburetor difficulty (I have never needed more than two pulls guaranteed by Toro) by NEVER FILLING the gasoline tank - only pouring enough into the mower gas tank to cut my yard to the finish for that day then leaving the mower tank as close to empty for storage with little or no gasoline left in the tank of the mower. At the end of the cutting season, I run the engine until it shuts itself off from fuel "starvation" being completely consumed leaving the mower tank empty AND the carburetor (which has a small bowl inside filled from the mower gas tank that holds fuel) thus becoming completely dry of fuel in the mower and empty before storage (my first thing done in the next mowing session is to add SOME fuel from a well sealed gas can, check the oil level, and pull the cord twice to start the mower). My experience has allowed my mower to start next session and next season after I add fresh gasoline to the mower tank and check the oil level carefully before each mowing session and especially assuring an easy start at the beginning of the next season.
As I explain above, these three "wisdom s" applied would certainly solve may of the poor rating experiences by other owners. This is a great mower, well engineered, and I was successful after a careful reading of the instructions and following these common practices for success!