I have th VS2121 and it's ok.Not a deep base but good enough.If you plan on blasting loud music with high bass then the VS2121 isn't for you.the Vs2121 is 2.1.You can't control the volume on the sub.I'm guessing the 5100 is alot better since it's a higher model.Check somer views online.I think my pops have the 5100 but he sleepin right now so i'll check for u tomorrow.
