SumatraPDF is fairly minimalistic, it is a single executable file that runs without installation. Foxit has far more features than SumatraPDF, it is more like the slim sibling of Acrobat (no insult intended!). (SumtraPDF.exe is something like 3.5 MB, Foxit's msi package is something like 70 MB, IIRC)

But Foxit never has given me any reason to complain. I have across a few tricky PDF files that took forever to open in Acrobat, and Foxit (and SumatraPDF) handled those without trouble. Plus, it installs a PDF printer, which is convenient on pre-Windows 10 machines.