What is the slight problem you have with the background plants?
I like it pretty well. The only suggestion I would offer is to make it a little less symmetrical. I think you've done a nice job and I like the selection of plants and rocks.
In some tanks that's what the aquarist is going for but when I look at your gravel, rocks, wood, etc. I get the impression you are going for a more natural look. If that is the case then a bit of asymmetry might help. I think you've made good choices in terms of plants and hardscape materials though so it's a great start and I particularly like the wood you chose.
I think you should put another Java Fern in between the two you already have. I reckon that would look sweet!
Other then that, I actually really like it. Love the wood.
Try moving the fern on the left forward a little and the one on the right across and behind the other a bit. Then try moving the two plants on the left front over to the right. This might make it look a bit less symmetrical.