I played the viola in high school! It was awesome being the only or one of a select few in every orchestra I joined. I've always loved the cello though, I think it has the most soulful sound of any instrument.
It's always nice to meet someone who's played the viola! I think it's one of the most underrated instruments in an orchestra, to be honest. But hey, I'm a bit biased. And I have to agree about the cello - its sound is so rich. I often get chills listening to it. Have you ever tried playing the cello? Playing the viola gives a bit of an edge when learning it, since they share the same order of strings.
No I haven't unfortunately. I don't envy the task of carrying a cello around, but damn if it isn't the most beautiful sound. I love the Piano Guys mostly due to their cello renditions of songs.