Rayzoon Jamstix 4 is the indisputably best "virtual" drummer VST there is. Initially I would have taken a few weeks to a month to really get an idea of what to think of a VST, but it only took me 24 hours with Jamstix 4 to know that I found something much more special than any other Drum VST there is....
When you hear the word drum VST, SD2 and EZdrummer often are the first names to come to mind. If you know how to program midi, the traditional options are great. However, not everyone can do that, and some multi instrumentalist artists only need a drummer as they can play all the others instruments themselves. This has been my problem as a classically trained pianist, flamenco guitarist, and metal guitarist, I have tried all of the old "drag and drop" MIDI groove VSTs.
Someone finally mentioned Jamstix 4 to me last week, and upon watching the video, I was in a state of shock because what I had been seeking for endlessly on forums, social media and everywhere else not only existed, it was in its fourth incarnation. mDrummer by Melda and Strike 2 by Air effects (Avid), and while they are great VSTs themselves that try to imitate the A.I. of Jamstix, they do not come close to what kind of automation is possible with Jamstix 4.
While it is a stand alone program, you cannot expect such a perfect piece of software to encompass ALL things at the basic level, and so it is great to use as a module for something like Superior Drummer if you get the basic version. In other words, you can write and arrange everything (live as well/on the fly) and you can play it back as well through the VST itself, but if you can send it to a drum program with your preferred drum "instrument" sound files, then you have that option as well - which is incredibly useful and open minded of the creator.
Melda's mDrummer is great for composing a MIDI track, but it is not a virtual drummer, and its live mode and general GUI is not easy to use. On the other hand is the overly simple Air Strike 2, which is a great BASIC tool for writing drum parts for guitarists or musicians who don't know how to program or write MIDI drums well. It offers a variety of styles and choices, and sounds, but not only are you "stuck" with the library of drum sounds they offer, but you cant route/send it to your favorite VST, forcing you to use the VST first, send out the midi, and then place the MIDI file in the arrangement of your other drum VST. Rayzoon was very smart for allowing MIDI bussing to VST's that a customer may have paid $300 for because the sounds are great...but what was missing was the "brain" of Jamstix.
As I said, since the digidesign eleven rack came out, Ive been searching for the perfect VST, but no one ever told me to look at Rayzoon. It's hidden secret of studio musicians, and now I know why I haven't heard of it since I've started to look for DAWs about 15 years ago: if people KNEW that studio musicians could "write' drums" that come out this perfectly with just about 5 clicks, producer fees/costs would go down quite a bit.
Im an advanced musician/instrumentalist, and for years I've struggled to write drums with VST's included MIDI grooves, downloading metal expansion packs, searching far and wide for the "perfect virtual drummer," and no one ever told me about Jamstix when I asked about 50 times over the course of 10 years on 10 different musician forums, "is there a VST that can automate composition?" - the answer is a resounding YES. It can do every style of music that you have the desire to record. Rayzoon's Jamstix 4 is the best drum VST ever made, and I am sure the $300 edition that has more sounds and sound files would make this the only drum VST you would ever need.
With that said, if you happen to be a metal guitarist looking for a metal drum VST, this is the only real choice if you want the best. With the metal pak add-on, this virtual drummer has a sound library worthy of competition with any metal drum VST, like the metal foundry. In fact, the drum VST is so good, that routing isn't necessary to another drummer, even if the metal foundry was at one point the gold standard for home recording metal musicians.
This is the only VST I've ever tried that goes so far beyond my expectations, that I had to inform the company that they are genius - literally. Get Jamstix 4.