Maybe a 6.5 or a 7.
It was a combination of things that had a National Treasure/2+3 POTC vibe to it. Rather than bank on previous formulas that worked for the movies they were used in, and those story lines, they should have come up with something different and new.
I think some of the action stuff was overdone contrived stuff they threw in to appease POTC fans. I didn't think the CGI stuff was all that great (usually I'm clueless and can't even tell, but...I could tell).
Generally, the story line kept me interested and I didn't find myself wondering when it was going to end. I kind of had more fun picking out things that reminded me of the ride, though.
The villain just wasn't smart or developed enough as a character, in my opinion.
Oh, and if you see it in the theater, don't stick around through the bajillion screens of credits for a possible post-credits scene. There isn't one. (Shame on you, Disney. You had to have known that some of us would think that, and after ALL those damn credits, we deserved something!)