H&R block for 3 or 4 tax seasons. It just makes you dangerous enough to know what you are talking about. It doesn't make you skilled enough to be a very competent tax preparer.

Some EAs are great though. The vast majority of the ones I have run into only are just above H&R block in their skills.

I would judge a tax preparer by experience first and then credentials. Have they worked at a tax shop where their work has been reviewed? You don't pick up the skills necessary to prepare taxes unless you learn them from someone. Most EAs I have run into learned on their own and haven't worked at a place where their work was reviewed.

I run into two types of EAs. The type that is sloppy and cheap and the type that is clean but doesn't take any risk and can't do complicated work. A basic sch E and C is about all I see from the 2nd type.