If your test is Tuesday, then definitely do the online version unless you do overnight shipping (call ADA to confirm if it's even possible to get it to you before your exam).
The online version allows interruptions, but it does not allow you time to review your mistakes. It also doesn't tell you your subject scores on each individual section, instead it tells you the # you have correct vs the # wrong. In order to convert this to an actual DAT score you can use the 2007 ADA conversion sheet (google it).