Using "Off brand" or "Will fit" filters to save money gives a false sense of economy. As said in other replies, micron ratings and filter construction are important.
"Cheap" bypass valves, poor filter media and the lack of it are common and lead to expensive engine, transmission and other "expensive" component failures.
You can buy a lot of filters for what a repair or replacement engine would cost plus the aggravation and the down time.
Not all filters are created equal. The top quality manufactures are careful in production to be clean,
"Production Dirt" in a filter is bad news.
Just because a filter will screw on or drop in, does not mean that it will perform correctly.
Just my 2cents