I have a ton of virtual instruments, plug-ins of all types, guitar amp sims of all types, and this one stands out on its own. I've been a steady user of Superior Drummer and their libraries for a few years now I just got this pack today and applied some of the plugs on drums, guitars, vocals, and mastering chain with a soul gospel group I'm recording & mixing, and I found several presets that fit my mixes very well.
I'm particularly impressed at a couple of things - how the transients are standing out, and how well the guitar sims sound. I mean, some of the guitar presets are jumping right out at you without being overblown or harsh like some guitar sims. Already I've used a distorted sim to fatten up a track that I'm doing today. It was that good, and it took maybe two minutes to browse through the browser to find it. (It's very helpful that everything can be labeled by style, instrument, genre, or effects.) Usually I have to browse for minutes on end just to find a decent preset on some of the guitar sims I own. I was hugely surprised at how good a simple plug-in made the guitar track just come alive.
I downloaded the Masters I & II, Drums, Toolbox, Modern Pop/Rock, Songwriter and The Mix Toolbox. At this price you can't beat it. If you are like me, working with several different groups and genres in my project studio, this takes some of the extra work of experimenting with different combinations and chains of plug-ins. If you understand the basics of mixing and how parts fit together, and if you understand effects & dynamics, you will get a kick out of these packs. I purchased these on a whim, but I'm glad I did. I feel like a kid who just discovered a new toy, but not one of those you'll play with for a while & get tired of & put away. I have a feeling I'll be playing with these for a long time.