Hi Adam,
Just noticed you didn't have any replies and thought I'd give you my opinion. Although I really don't know what the official opinion of DO schools is, I think it can only help you to do research. While many DO schools don't have a lot of research themselves to offer now, many are trying to increase these opportunities, and I think they all recognize the value of your having research experience--it requires you to dealve deeply into a scientific problem, learn the literature, and think critically.
So I think research can only be a plus for you. Now the real question is...do you personally want to do research? I have been doing research for several years now and have discovered it is not what I want to do full-time. But I have enjoyed it and have learned a lot from it. So if you think you might like it, go for it. But if you think it will be a torture for you and you're only doing it to try to get into med school, then I would just do something clinically-related that you'd enjoy more.
Hope this helps a bit. Good luck!