In my experience, (I've used TTX for 20 years now) those who file early risk creating a nightmare when they have to amend later.
A person that e-files in March-April will typically get their refund in 3-6 weeks.
A person that files in January the day the IRS opens e-filing may end up getting nastygrams from the IRS delaying their refund, as well as requiring them to amend their returns. Amended returns can take months to process, and any additional refund that may be coming can take up to a year (or more) to get. Just my two cents.
