As stated above, the monitor brand is not so important, more are room acoustics.
As I only have little space, I use the very small Adam Artist 3 with a sub 8. Walls and ceiling have absorbers from HOFA. But key to the neutral sound is the frequency correction with the dbx Driverack PA2. I had severe room nodes that went up to 16 db in some bass areas and not enough space for bass traps. With the dbx I was able to correct them in my listening position so I have now an almost flat frequency curve in that spot. This is day and night when I turn the correction off. For spotting problems closely in a mix I use the beyerdynamic 1770, worth every penny, but the open 1990 is maybe a bit better, if you have a silent room. If you have the money, get a sennheiser hd 800S.
The DT 770 from beyerdynamic, which use a lot of people, has a nice flat frequency curve but is lacking in the details, the 1770 is much more accurate (at 4 times the price).
Frequency correction can also be done via Software-Plugins (Dirac, Arc 2 etc.). I used them for a while and the work well, but its easy to forget to turn them on and off when you change to earphones and back. You also have too route your synth through the PC which is annoying, so changed to a permanent hardware solution with the PA2.