It was watchable. As for the zombie genre in general, I've never understood the military strategy against them. If you had superior firepower, why the hell would you sit back and wait for them to come to you? What would a wave of zombies do to a rolling column of tanks? Die...again. Instead of circling the wagons, establish a front. How many men do you think are bayoneted in open terrain in today's military? Zero. A big ole wall o zombies wouldn't get within 300 yards of an entrenched assault force. Don't even get me started on air superiority. Now if the disease was spread by airborne transmission and had a suitable latency period, that changes everything.
The book had a pretty good explanation as to why conventional warfare methods didn't work well against zombies. To sum it up:
1) Most high powered explosives kill people via over-pressurising the surrounding area. Humans can't survive this because it liquifies the insides and/or overloads the nervous system and shuts it down. This doesn't affect zombies.
2) The only way to kill a zombie is to destroy the brain. Blowing it in half or blowing off limbs will slow it down, but won't stop it. Armor piercing rounds are useless (unless you hit a head).
3) Armies are only as effective as their supply lines. They run out of big ordinance pretty quickly, and the tanks and aircraft that are the backbone of a modern military force require a lot of specialized maintenance and parts to run. Every service tech you lose to zombification is one less you have to maintain the nice stuff.
4) Assuming advanced spread of the zombie plaque, there would be over 150 million zombies in the continental U.S. alone. So - imagine that you are facing a Greater Jackson Area sized horde with a division of artillery. Sure, you'll probably kill quite a few. Then you run out of ammunition, and they keep coming. Troops need to sleep - zombies don't. Equipment breaks down - zombies don't. At best, you are fighting a withdrawal action and leading a crapton of those things to wherever it is you think is safe.
tl;dr
There are ****-tons of 'em and you'll run out of ammo eventually. Also bombs aren't nearly as effective as you think. Plus they don't sleep.
I'm gonna crawl back into my mom's basement and strategize some more on the upcoming zombie apocalypse.