The Marcus Fenix trilogy ends on a high, though not perfect, note.
The classic Gears gameplay is as fun as ever, even if there isn't much challenge, much like Gears 2.
My biggest complaint would be in the handling of the squad. A few new characters are added and necessitate splitting Delta Squad apart and sending them in separate directions. The idea is fine, in principal, but the newly added characters are so incredibly boring that they dilute the squad's appeal and energy and make it feel like something's missing (because something is). Don't worry, though. Delta Squad reunites for the climactic Act, just as the action reaches its apex.
A great finish to a great trilogy.