BestMark is a legitimate company. However, I would definitely use the link found on this website's list. There are lots of scams out there in which the scammer disguises him/herself as a real MSC.
As for whether or not it is a company for which you want to work, @JASFLALMT is correct: We all have different opinions based on our personalities and geographical locations. I did quite a few shops for them as I got going, but them found opportunities I preferred with other companies and now rarely shop for them. However, they do, every once in a while, offer what I consider a "gem" of a shop.
Hard work builds character and homework is good for your soul.