Briggs and Stratton and Kohler engines are considered quality components. Neither is likely to be better. However, the Briggs and Stratton brand is more popular.
Kohler for sure
Briggs engines call for a 30W SH or better
SAE 30 SF or better rating
Onan no longer makes engines. But with the older ones it is hard to say. Both had very good engines. Some better than others. I would say Kohler had the better single cylinder engine after Onan stopped making the LK. Onan had better RV generator engines. On the larger units they were both the same in quality and support.
My research has shown it to be a Fram PH8170, but IMHO you'd be much better off going with a NAPA (Wix) filter, FIL 1056. i also just used a fram PH3614 in place of a 492932 since it was the filter i used on my kohler engine. the stp3614 would also work, if still available. these filters are about 1 inch longer, but if you have enough space they will work fine.
Fram says Competitor Part Number kh2505025 Not Found. Wix says KH2505025 CUB CADET Part Number: 51056 Principal Application: Various Lawn & Garden Equip. + Small Tractors w/Briggs & Stratton, Hatz, Kawasaki, Kohler, Lister Engines But if you want a Fram the Wix number crossed to PH8170 or PH8172 I Advise the use of the Wix filter it is a better quality filter.
Briggs and Stratton does not release specific compression values. Anything above 120 psi should be just fine, around 90-100 and you're most likely due for a rebuild. A better test is a leakdown test, with can help in determining where compression is being lost.
They are very similar engines. Someone that has had an issue with a B&S in the past will tell you to get the Kohler. Someone that has had issues with a Kohler in the past will tell you to get the B&S. On paper, it looks like the B&S offers a tad more torque, so that's an added bonus. I'd go with the B&S personally. When I think of Kohler, I think of toilets and shower heads. When I think of B&S, I think of small engines. However at least the 21Hp that is used on the husqvarna has a serious problem with the carb....has a solenoid on the bottom of the fuel bowl that gets hot and boils the fuel when you turn it off. Causes clogged jets.
The most important thing is the engine. The rest is all the same. Look for anything with a Briggs and stratton engine and you will be fine. What a dumb answer. Deere by a landslide!
Both are about the same both have a Briggs & Stratton engine Troy -bilt is just a expensive name like John Deere or Husquvarna
Kohler will be the best choice for you, although the price is more expensive.
Briggs and Stratton recommends Synthetic 5W-30 for the best protection at all temperatures. This weight gives better starting with less oil consumption. During winter months, when temperatures dip below 40 degrees, 5W-30 is recommended.