Very interesting - I particularly liked the opening into the Cello theme at 26-29, as well as the upper strings at places like 32. And you can't beat a viola opening (although I may be biased, Viola was my first instrument and still my main one) .
I'm not sure about the ending though - it works, but it seems rhythmically different to the rest of the piece. There are a lot of very interesting offbeat and dotted rhythms there, and some run-type figures, and those seemed to disappear in the end of the piece. Not that it was a bad ending, just seems unusual when looking at the score.