When I first got my upright, the shop gave me, along with a fiberglass bow, some rosin. Trying on my own, I wasn't able to get a very good sound from the bow. At my very first lesson, my instructor advised me to throw away the rosin they gave me and buy some Carlsson. I did that and it made a world of difference.
About six months ago, I noticed he was using a new rosin: Pops rosin. I knew from reading various bass player forums, that Pops rosin is very controversial. Everyone has an opinion on it, and everyone either loves it or hates it. I asked Doug what he thought of it, and he said that he used to use it all the time before and was just going back to it. His only complaint is that it melts easily.
After I got my new bow, I was working with Doug some more and he suggested I give Pops a try. So I finally broke down and bought some last week and used it last night during orchestra rehearsal. So far, I'm falling into the hate it crowd. I get a very screechy sound at the beginning of pulling the bow. However, I can't help but wonder if this noise isn't just the different rosin amplifying my own poor bowing technique. As such, I'm going to keep using it for a while before I make up my mind completely. I do like the idea that it's made in the USA, so I'm not adding to global warming by having my rosin shipped from Sweden. Besides, Doug's been right about everything else so far.