That big piece on the left catches my attention too much and once seen it's all I see, however grown in it could be a very different matter.
On a side note looking at your flickr you have some amazing scapes so I'm sure you have a great vision for this qnd I'm eager to see how it develops.
This one in particular is simply stunning! Just wow!
I agree with Danny. I think the left one stands out because it's more green than the other rocks, so perhaps when planted not a problem.