I use tab delimited because lots of data can have a comma in it.
eg 25, My Street, mySuburb
caravan parking, glider rental, and trailer parking fees.
sent one email, two letters, and even phoned him, and still not payed
so these would mess up the insert. But the data that I insert regularly, which often has commas in the actual data, never has a tab, and I think that most other people are very unlikely to encounter a tab in their data.