Per your request:
I'd give it a B-.
I've seen much cuter/better kids movies.
There's a healthy bit of adult focused humor so it's not a total sleeper but I left feeling like I'd seen a cartoon on TV instead of a feature film.
The kids? They could watch paint dry at a movie theatre and think it was the coolest thing ever. Add popcorn? I'm the coolest Mom ever and that was the best DAY ever. Catch my drift?
Kinda closer to the end there's a couple of music video scenes where the background is a solid color and they're focusing on slow mo's of 1 or 2 characters with music playing. Jace turned to me and said "Is it OVER?" really loud. God help him - he thought the credits were starting.
Other than that they both did fine. Not sure the 3 yr old really followed the complete story line (it really is Romeo and Juliet but with a more kid friendly ending). The 4 yr old seemed to get it pretty well though and talked about the story off and on for the rest of the day.
If you're an Elton John fan you'll find extra enjoyment as it's all his stuff (some old and some new).
That's all I've got.
Sorry - not destined for a career in film review!