FET Amplifiers (MOSFET or JFET) have low input bias current and low input current noise at lower frequencies. These specs are beneficial when designing signal chains to interface with high impedance sensors. It's important to note that the current noise in a FET Amplifier increases at high frequency and this could be problematic in some applications. Recent product releases (ADA4510-2 and ADA4620-1) have started to characterize this behavior and provide plots in the datasheet.
ADA4510-2 Current Noise Spectral Density vs. Frequency
The Signal Chain Designer tool has added the capability to model current noise vs frequency and I encourage you to watch the training video that goes into more detail on the subject. It even shows some interesting results (green curve below) that show up at high frequency, in a unity gain buffer configuration. This is due to the negative input current noise into the output impedance of the amplifier.
ADA4510-2 Noise Spectrum components shown in Signal Chain Designer
If you want to learn more about FET input current noise, here is a great article that goes more in depth. If you are curious about current noise in chopper amplifiers you may find this article interesting as well.
If you have any questions on this topic or the Signal Chain Design tool, feel free to ask in our Engineer Zone forum.