Whether you are Alliance or Horde makes aboslutely no difference that I can think of.
The Scryer level is closer to the flight point, as well as closer to the ground. The former is important if you are impatient to get around Outland; the latter is important if you keep missing the elevator (Aldor elevator you will die if you fall).
The Aldor level has an exit to Nagrand, so there is slightly easier access to that zone. This may make a difference if you want marginally quicker access to it - if you are an LW maybe, or want to do lots of PvP at Haala.
Obiviously all that is moot if you have already picked either Aldor or Scryer. Then you will want to bind at the inn of the faction that you have chosen.
Thranathiril