The reason for having an isolating option is to protect your hearing in noisy environments. If for example, you are riding the subway and have to crank up the volume to drown out the train noise you are running the risk of damaging your hearing. If someone wants to get your attention they will be able to no matter what headphones you are using. If you are more worried about situational awareness
then be aware that any music while out and about will be enough to distract you.
Anyway I'm getting off topic, get the ones that appeal to you and test them out. They should all be pretty solid choices. If you do not like them or there is a problem you can always return them.