I discovered this Liebenzeller rosin first yet in about 1998 and became definite fan of it since then. Being professional soloist cellist I tried several leading rosin manufacturers products but couldn't compare this one with any "non-metal" rosin. Really durable, with much less dust than any other rosin, it helps to produce wonderful warm and projective sound.
When my first piece of Liebenzeller Gold IV got out, I desperately tried to find where to buy the next one for some years. Than I discovered a variation of Liebenzeller made by Larica, and that is the only rosin of similar quality!
In fact, currently I use Liebenzeller Gold IV as most versatile option when playing 19-21 centuries music; Liebenzeller Gold III when needed a more light sound in chamber music; Larica Meteor IV Metal rosin for solos with orchestra (it gives the most bright and strengthen sound) and finally Larica Silver III Metal rosin for Baroque music played either cello or viola da gamba.
I always recommend Liebenzeller and Larica for all my music academy students as well and happy to recommend these brands to anyone from beginners to professionals. It indeed worthy of its price.