Static text, assuming it's just opening a file in the OS and dumping it, in theory should always be faster unless your directory has thousands of files in it. The file open process is the hit here, you need to keep the number of files in a directory low as that's where it burns time.
Next, text files never crash, MySQL does. I run a directory and auto-scan for broken sites all the time and I see a lot of dead sites with some error about a failed table or can't connect to the database.
No real right or wrong answer, decide what's best for you.