What do you think would be the search terms used in the national SE. If it's kwdPrse change for that and if it's KwdoPhrseo go for this one.
Try overture to see wich is the most searched in you targeted market (if you're lucky enough to have overture available for them :))
Otherwise go for both with enough changes between the two sites to not to be similar and be picked up by google duplicate algo.
Good Luck ;)
Leo
Exactly. As always the starting point is research - what do users in your target market want, what and how are they searching for your offer?
If you got that you can see if a domain name with that keywords in makes sense, is available, sounds good. Get input from native speakers on that.