I actually already own both. I got a great deal on them, but now I just have to choose. I know the first thought is just listen for which is best, but I don't have an ear yet and don't know what I would be listening for.
I appreciate this as a valid concern. If you spent all of your life (thus far) listening to music piped over Walmart PA system (or whatever), you could easily be wooed by the extra bass of speaker XYZ only to discover later that the midrange is not as clear as it would be on other speakers that cost the same!
I have a suggestion - get a decent set of headphones and use them as a reference to compare your speakers against. (see what I did there? You thought you had already bought everything and I just gave you a viable reason to spend more!)
Tell us your budget for headphones and we'll give you some suggestions, but generally Sennheiser makes fine headphones across the budget range!
Even though I have some very nice speakers and spend about 7 hours/week playing in jazz bands, I still go to my headphones on occasion to determine if a problem is due to the speaker or the recording!