So the Briggs engines are crap.
Who BUILDS the good ones?
I can't remember who makes them, it is more a partnership than a rebadge. All of the Vanguards I have seen were made in Japan though.
I have got a JD mower and my yard vac with Kohlers on them. Experience with them is limited to a few hours so far but they run VERY smooth. No problems starting, run clean and have reasonable power. As the gear they are on is well used, I don't think they are particularly fresh engines. No experience with Kohlers other than this and never worked on any so see how they pan out.
Kohler's are in a whole different class from Briggs and Tecumseh. They are the "heavy duty" engines. They have always been very well made and one pays a premium for them here in the US. They do have a cheaper line of engines out now aimed at competing with the import stuff that has had a few issues.
Did have a couple of Techmseh's many years back and they seemed like garbage too. I have no idea what became of them. Haven't seen them in years.
Tecumseh's have been junk for a long time. I think they went downhill sometime in the '70's.
Honestly , in the power equipment world in the US Kawasaki has taken over. They have been slowly gaining market share for the last 20 years. They make a very good product that has held up to the abuse of commercial landscape crews. Some of them are made in Japan and some are made here in the US. They and Kohler seem to battle for king of the hill these days.