Mirin

Your site introduced me to mirin and I love it and the flavor it gives to food. The first bottle of mirin that I found (at an upscale grocery store - not asian) was very dark brown. Not as dark as soy sauce but almost. I'm almost out and went looking again (my upscale store is out of it). I found Kikkoman Aji-Mirin which looks like white wine. Is there any difference in the light vs. the dark or is all mirin basically the same? I haven't used the light stuff yet so don't know if there is flavor difference or not. And since I started my hunt, I'm seeing much more light colored mirin, almost no dark. Inquiring minds want to know...