When accurate audio reproduction is crucial, you need a pair of accurate Monitor speakers. Studio monitors are not just speakers, but they are designed to do a stricter job than standards home audio or hi-fi speakers.
Some people like to do mixing just with headphones, but Headphone mixes often lack depth and wind up being very in-your-face and loud. In general, mixing on studio monitors is always preferable.
Which one is the best Studio monitor? In my opinion the one that will give you a flat accurate response of the mix. A well-mixed track should sound great on everything from laptop speakers to a high-end hi-fi.
Your budget plays an important role, but that does not mean that expensive monitor’s speakers will always give you the most accurate mixes. You have to trust your ears as well. Your speaker’s monitors brand may boost certain frequencies more than other but, practice and trained ears are the foundation for a well-mixed track.