Is it better to be an ICU or ER nurse in the miltary?

I know it's a matter of opinion and personality, but if you could speak to a few variables I would appreciate it:

1) Is there a higher demand for ICU or ER
In the Army the ranks of ICU and ER nurses manned at about the same percentage of billets.
2) Potential for rank advancement
In the Army both the ICU & ER nurses are 66H with additional skill indentifier.
3) Potential for deployment
Both have high deployment rates in the Army
4) Working conditions relative to civilian counterpart (ie. generic military ICU vs. generic civilian ICU)
Like in the civilian world it varies by hospital
5) Is there anything especially beneficial about one or the other in the reserves vs. active duty
If you stay in the service long enough for retirement (20 years) you can start drawing your retirement pay as soon as you retire from active duty. In the reserves you have to wait until your 60 and then it decreases by the amount of time you have been activited since 2007 or 2008 when the law was changed.


Thanks for any input on any of these themes!