I actually saw this 2 nights ago, but I didn't have enough time yesterday to write a review. Work was INSANE. Sadly, it wasn't because of Gnomeo & Juliet. Justin Bieber's Never Say Never was the practically only movie I directed people to last night.
Now Gnomeo & Juliet, wasn't perfect. It of course is a spin off from the Shakespeare play Romeo & Juliet, and I thought the story was actually pretty clever. Feuding lawn gnomes? Instant funny!
The very beginning of the movie, a tiny lawn gnome with a giant red hat came out to do the famous "prologue" Romeo & Juliet has always begun with, only he didn't get to finish the whole monologue due to a "hook" and a trap door trying to get him off stage. It was because of this beginning, I knew it was going to be exactly as I expected: making fun of the story. Which, personally, I'm all for. Romeo & Juliet is one of the worst Shakespeare plays, in my opinion. Also, throughout the whole movie there are TONS of other Shakespeare play references. The theatre geek in me was geekin out. ;)
The movie overall, was pretty cute. As you're introduced to both The Reds and The Blues gardens, you understand how funny (and fragile! *plot point*) these characters are going to be. First off, it's sort of a Toy Story feel to it. They come to life when the humans aren't around, but when they return they get back into place, frozen. They're all pretty much doomed to look the way they look. For example, there was one Blue gnome that sits on a soccer ball, and when the humans left, he stands up, and the soccer ball is still attached to his behind. Poor guy.
Gnomeo, is a blue, which, of course, makes Juliet a Red. Gnomeo was voiced by James McAvoy and Juliet by Emily Blunt. Both brilliant English actors. It seems strange though, that both gardens were obviously English, but the humans that lived in the houses weren't. I mean, I understand why they're English (since the R&J story was), but why not make the humans too? Ah, well.
The animation was pretty good. You didn't need the sound editing to realize that these creatures were made of ceramic material. It even makes you nervous that these little guys are going to break (aka DIE) at any moment...
The music was an interesting (but good) choice. It was modern. But, you can never can go wrong with Elton John and James Newton Howard! It wasn't a 'musical' exactly, but there are sequences where the songs take over for a sort of montage of action.

I seem to have more trouble critiquing animated films...or maybe it's just this one because all I can think of doing is comparing it to R&J...So, I'm just going to end it here.

Should you see it? If you're bored it's a good choice to go with while you stand in front of the box office. It was nothing special enough to RUSH out and see it though.
Other note: Did I mention it was in 3D? I almost forgot that part. Probably because the 3D was pretty much useless. You forget you're watching a 3D movie, and I hate when that happens. Not that I want stuff thrown in my face every 5 minutes, but it really could have been fine as 2D.
Take How To Train Your Dragon, for example. Beautiful and perfect use of the 3D.

I Am Number Four comes out next weekend, and my theater is showing it in D-Box (motion seats) sooo I'm pretty darn excited for it!