I used in the past Zoom H2, Zoom H4 and Zoom H6. All are very good portable sound recorders, and there is big difference between them. If you can not make decision to choose between Zoom H4 and Zoom H6 I would recommend Zoom H6, because the available audio levels knobs and much user friendly display are big help. Advantage of Zoom H4 were – in my opinion – guitar amps and effects simulators, but if you don’t need any guitar stuff, Zoom H6 looks like the only option. And, on top of better user interface, Zoom H6 enables you to use different mics, depending what you would like to record – replacement of the optional Zoom mics is very easy, and they click into position with reliable connection socket. For professional usage something like comfortable replacement of mics really matters.
In standard configuration in Zoom H6 plastic box you will find additional stereo MS Mic. However I did’t use it. For what I needed the main XY stereo mics were perfect and except that I could use XLR input. Compared to other of the same class, flexibility and – first of all – sound quality make Zoom H6 first choice, especially for film making. In situation where you use DSLR for video recording Zoom H6 can be used as external audio recorder, because usually onboard DLSR camera mics produce bad or very bad quality audio. Removal of hiss and other kinds of noise present in DSLR audio track produced by DLSR mics can take huge amount of time or, usually, is not possible without decreasing of audio quality.
There are some editing options onboard on Zoom H6, for instance you can cut or modify records or do some basic things with audio tracks, but for editing I used external audio editing software like Audacity or Adobe Premiere Pro and in general I recommend to make backup first, before you start editing, especially in any portable audio recorder.