I've had my upright for about 2 years and for the entire time I've been playing the factory strings (I'm not sure what exactly they are) but I don't really like them and would like new strings. I've never bought strings for upright before and don't really know where to begin, as they can be very expensive, I don't want to buy a set and not like them and be SOL. I play jazz and am looking for something bright with a nice sustain. Any suggestions? gut or no gut? I've checked out the Pirastro Jazzer strings, does anybody have any opinions? I'm open for anything at this point. Thanks!