On the one hand it can be good to expose oneself to different sources of the Word being preached. I mean, when one studies a passage in the bible, it is sometimes helpful to read it in several translations. However, in terms of building fellowship with other believers, that happens best with a commitment to one church.
Maybe your friends are just having a hard time deciding.
Are they single, married, with kids? When I was single, it was kind of a thing to regularly visit other churches looking for fresh meat. I didn't do it, but I knew several who did (and actually found spouses that way, so go figure). I've also known families who split themselves between one church the kids really relate to, and one where the parents get more out of, when they couldn't find one that had both.