Is it fun? Somewhat.
Is it worth renting? Yeah, arguably.
Is it a good game? Yes.
But is it great? Not even close.
Repetitive content, lack luster combat, removal of most RPG system mechanics found in BS 1 and BS 2. The game is nothing like the gameplay trailers from a year ago, in fact those videos were much better. The story as much as it seems differs from the reports, is incredibly simple for anyone with even a few years of college or intelligence, isn't so much plot-hole filled as much as uninteresting to be honest, and the atmosphere loses itself time and time again. Even the portal concept is much more mechanical rather than innovative and interesting.
BioShock Infinite is the most overrated 7/10 game I've ever played. And I have no idea why people refuse to see.