Your image is very solid. Your composition, resolution and depth of field are right on. Something about it seems a little off though. Maybe too much green. It has a very unreal feeling to it. Just my opinion. Take care.
I honestly thought this a photo when I first saw it. You certainly devote lots of time and effort to these and your fractals and I admire the work that many of the CGI and fractalists produce because of their focus and creativity, you included.
Ah, I didn't see this before -- I particularly like the fine texture on the rocks, and that rippling clarity round the water plants! Maybe the water could be more blue to reflect the sky.
I've decided for now to stick to 'Final' quality renders... I tried a Final and a Superior, and the Superior took much longer but looked no different (except in shadows/lighting... I haven't found out yet what it does differently, but I don't think it means higher quality anti-aliasing). Hmm...