My current understanding: If you have married for two

years when you apply for green card, or your application is approved, you should get a permanent one instead of conditional one. Or else, you will get a conditional one which will last 2 years.

So you can choose to get a conditional card now, or wait until when your have married for two years to get the real permanent one.

If you have a confident marriage, you should definitely choose the the first option because conditional card is virtually the same as the permanent card, except that you need to file a convertion to permanent card 3 month before the ending of the two year period.