motorola vs hts sense what's the difference between them ?

[unkledude]

so i went and saw and played with the new photon 4g yesterday from sprint and was really impressed with the phone but the motorola rep had said that the motorola was using/ running some kind of muzz something and the htc 3d ( just a reference) was using htc sense.

what are these and how does it effect the phone and it's use overall. i'm very inexperienced with smartphones and their tech stuff so i really don't know the difference of one to the other.

thanx to all how reply