While a number of restriction enzymes have isoschizomers (i.e. other enzymes recognizing the same site) in most cases only one of those is commercially available. So use that one!
you need to choose the cheapest one and choose one of the most cost effective isoforms... I don't know whether it's important to you to save the costs or not, but if so, I would prefer to use the cheapest one .... ( of course if the results are the same )