Virtual instruments can be very divisive, I myself was very much against them when I first started creating music; however throughout the past couple of years I have very much seen the utility of them and in this post I will share my thoughts on the topic.
My first interaction with a virtual instrument was around 4-5 years ago when I began creating demos for a project I was working on. I was working with free drum loops from a primitive VST to try to cobble together the music that I had envisioned in my head. This was a very painstaking process that was born from necessity as I had no one else to collaborate with at the time, and this is the first major advantage of VST's. If you are hyper-creative like myself then VST's allow you to create to your hearts content, even if you can't play or don't have the ability to record all of the instruments you want in your music. Over the past few years I have manage to gather a group of VST's that give me much more freedom than the old drum loops I used to use and now, as shown by my band Sloan and The First Gentlemen's debut album Axiom, I can create an entire album without a drummer. This would not have been possible without VST's.
Another aspect of VST's that is of great benefit is the level of customisation available. With drums in mind, through a VST you can change the drums, velocity they are hit, you can even change what is being played entirely. If you record a drummer you get what you get and the only way to change it is to go through the hassle of getting the drummer, the equipment and the time to re-record it. This also applies to other instruments as well. This level of customisation allows a degree of freedom that I feel has enabled me to create at a level far beyond what I could have 5-10 years ago.
Additionally the VST's that are available today sound so good that, in the right hands you can't even tell they are programmed at all. The programs I use (GetGoodDrums, EZKeys, Melodyne, etc.) allow me to write something entirely on my own for fun and then turn it into a streaming ready track. This combined with my years of experience recording, mixing and mastering music has in no small part created Songplistic.
VST's may be controversial, and there are certainly decent arguments against them, but for me they are indispensable to my workflow and without them, well there wouldn't be a blog to read right now!