It is a matter of taste.
Both are very competent and feature rich CAD packages. Based on their level of release, one will have more functionality in areas over another. Have you installed the trial versions and created your typical parts on it, from initial concept to release? Give yourself plenty of time to work through all your issues and make sure you have access to someone who can answer any of your questions.
Have you asked your rep about customer support?
My previous company used SW. I am now with a company that uses SE. I do manufacturing tooling at both companies, so my "products" are the same. Both work just fine for each. Personally, I prefer SE. The workflow fits better with the way I think and I feel I get better response from their customer support. SE newsgroups are also moderated; you get less trash talk, more helpful posts without having to waste time weeding through garbage, but they don't sensor, at least not in my experience and I've had some pretty choice words about SE. Of course, Eng-tips has forums for both.
I can't speak enough about gaging their customer support. Both products are still maturing. There are going to be defects, bugs, and inabilities. The trick is to develop suitable work-arounds. All CAD companies I know, when you call customer support about a bug, will say that it is fixed in the next service pack or release. That's great, but I need to release a design now! SE support sticks with you on the phone, over the net, or through email (your choice) until you are satisfied with the result. They will help you develop work-arounds in order to get the job out the door.
Good luck with your choice. It is not an easy one.