I know this is a very late reply, however:

Having a deportation order is an additional inadmissibility.

For example if you're EWI and you marry a citizen you will not be able to adjust at all. You will not be able to file an I-601 as if you leave US while having a deportation order you're considered deported, if you leave on advance parole they likely won't let you in due to the deportation order, you'd need to then go through I-212 and that only gets approved only in the most dire of events (ex. your spouse has cancer).

Also if the I-601A provisional waiver will finally come into effect, you also won't be able to benefit from it. As that is used only to pardon EWI only if you are EWI and not inadmissible in any other way.

Also if you are / get under* 245i you will not be able to adjust until the deportation order is overturned.

* - You can get under 245i by becoming a spouse or a step child (before you turn 18) of someone who's a main beneficiary of a 245i petition before that someone receives their permanent residence. You are then a non-grandfathered derivative beneficiary. USCIS will allow you to adjust, but only through your main beneficiary.

Bottom line, if you can get rid of a deportation order, do so, it will always help in the long run.