There are many samplers / romplers, but this one stands out. Most importantly it is a 64-bit (32-bit is also available) GM compatible plugin. Since SampleTank abandoned GM there is almost nothing available for working with your SF2 soundfont libraries or files if you need a GM compatible synth in a 64-bit environment. I searched for something like this for a long time. I like this plugin for many reasons. First and probably most important one is the ease of use. It is a straight forward 16 Channel Synth with elegant classic appeal, that is not about the "looks", but functionality.You can adjust many parameters, transpose, layer channels and do many other good things with it. Plugin can output (stream) 16 channels of audio simultaneously for recording into DAW.
Probably the most significant points are that the plugin is very affordable and the developer is devoted and listens to user feedback.