what is the swc skimmer rated for? if it is rated to fit your tank i would go with the swc. the reason is because the ev400 would need a pressure rated pump to run it the equivalent of a mag18!!! mow adays there are far mor efficiant skimmers which use alot less power.
oh and the ev400 probably would be more powerfull but an extra pump in your system could add more heat. what pump where you going to use to run the ev400
Is this a new reef? If it is I would wait in the beginning. No need to rush and get one immediately you will have some time be fore is necessary . How ever you could use the time to save and get a newer one a little bit later.