All softsynths that are basic such as this one are not very CPU intensive and this is no different. I only have a Gateway 2.0GHz dual core 2GB RAM computer not even made for music and Vanguard is not a strain at all. Not integration problems with my midi controllers in FL Studio. Vanguard never really crashes either. It's definatly a stable plugin. I've been using this plugin for over a year. Always got good perfomance out of this Vst.
Now to the sounds, to be honest the presets are not very good. I do enjoy the gates and some arpegiators, but the leads are pretty generic. This doesn't mean the plugin isn't good. You can, of course, create your own sounds very easily.
Creating sounds in Vanguard is actually a very easy experience. Since all the filters, oscilator controls, gates, arpegiators, etc are already there right on the main interface. There is even a "Fatness" control. Usually it detunes the sound too much if it's used to drastically but if it's et right it can really help out the sound. I personally love Vanguard for the gates. It's so easy to program them. The LFO, Reverb, Delay, envelopes, and all the types of filters are easy to mess with.
One thing I like about Vanguard is the fact that there are so many wave shapes. Some that I don't have in more expensive plugins. One to check out is called "Digital".
Overall this plugin comes in handy if you are into creating your own sounds. If your a preset guy I don't think you will last very long with this just because the quality and quantity aren't really there. Not a bad product. Easy to create and tweak sounds. Surprisingly simple to use, yet powerful. I'd recommend this if your into creating sounds. If your not, don't buy it.