According to Wikipedia, some of the actors in this movie have implied or even stated that the mediocre reviews received by the movie are partly because of the predominance of men doing reviews (the "8" are all women). So you can feel free to discount my review right now. Or you can consider that the movie is getting mediocre reviews because it's just not very good and it has nothing to do with gender.
The movie opens with Debbie Ocean (Sandra Bullock), sister to Danny Ocean (she was never mentioned and certainly never seen across three previous "Ocean's" movies) having a parole hearing. Exactly like the beginning of "Ocean's Eleven." But less appealing. And after her release, it became clear that she simply doesn't have Danny's charm. George Clooney was spectacularly charming as Danny Ocean - but it wasn't just Clooney himself (although that really helps), but also the script (and Brad Pitt, and Matt Damon ...). Bullock is graced with neither: she doesn't have Clooney's charm, and the script makes her a bit mean and unpleasant. Cate Blanchett as her best friend neither helps nor hinders, despite being distinctive: she doesn't come across as any more appealing. And so it goes as they add members to their team.
The heist was acceptable, but not great. And just like the previous Ocean's movies, there's a heist-within-the-heist that's only revealed right at the end (which doesn't particularly improve the whole thing). It wasn't very funny either: they were tossing out jokes, but all they got back from me was a shrug or an occasional smile. Not a single laugh. There are scenes in "Ocean's Eleven" that I still laugh at after multiple viewings.
It's not a terrible movie, but I would encourage you to re-watch the excellent Clooney version of "Ocean's Eleven" rather than watching this.