I've had Jamstix for quite some time.
The thing I like about JS is that after you load the kit, the style, and select a drummer, you simply click playback on the DAW and JS creates a part for you. Everything is editable from the EQ and compression to the size and tuning of the pieces of the kit. You can also vary the busyness of the kick or the snare, vary the hit power, ride the cymbal bell, and literally dozens of other parameters. It all depends on how well you want to learn JS and how deeply you want to edit it and control it. OR...... you can simply load the 3 basics and let it run. All you need to do there is tell it where the song starts and where it ends. JS will handle the rest. As a non-drummer, I like to say, Jamstix does the "heavy lifting" for me.
You have to learn a few things about editing and song creation and getting around inside JS to really get it's full potential working for you. Once you have that, it's actually fairly easy to work with.
They sell lots of drum kit sound packs and percussion add ons for JS BUT..... it will also recognize and be able to use the sound packs and kits from many of the other major drum synths. I have Battery so I've added several Battery 3 kits to it.
You should go to the JS forums if you are considering buying it and read the threads there. Sign up and ask questions as well. I will say that from my experience, I had a few problems early on and their internet support is second to none. It seems like (at that time) Ralph was always on. He took a personal interest in handling my problems and solved every one of them in a timely manner.
I don't use drum synths too often now.....I use the drums in Band in a Box mostly, but on occasion, I like to pop JS into a project to get a slightly different take on the drums.
If they still offer the free demo version, just DL it and give it a try. That's what I did and needless to say, I loved how easy it was to work with and the drum tracks it created were so much better than the ones I was creating at the time with point and click midi. If you end up buying, just be sure to totally remove the demo version BEFORE you install the full version....that was one of my mistakes that caused issues.