You definitely want to enter all of the information before you determine that one is right and one is wrong. In all likelihood in the end they will match perfectly and if not, then the most likely reason is an entry error in one or the other.
The number you see when you get started is nothing but an estimated - and it is based on some assumptions that are clarified as you go through. One is likely assuming something the other isn't, until you get to that question in the program. Also be sure to double-check all of your entries to be sure there isn't a number typed in reverse or some other such thing in the end that can cause a difference. The tax is the tax, and unless you make different entries in each program you should always get the same answer.
You may also want to wait until all IRS forms are availble. They aren't currently which means both programs are likely missing some data, and some could be key in your situation.
