Which aquascape looks best?

i say for the 1st and then 2nd # because it gives amore balanced look, depends also how you place plants in there!!.
 
For me it'd depend on the fish. #5 or #1 for loaches. #2 for catfish. #2 or #4 for mid-level swimmers. #2 for a pair of dwarf cichlids (if the rock forms a cave like it appear too).
 
Photography is strange...or maybe my eyes are. The first and last look totally (well, very) different from 2, 3 and 4. 1 and 2 look like gray granite with some green mossiness in spots and other places light and dark blues. And the substrate looks like coarse-ground coffee at about the light city roast stage, brownish-tan.

The middle pix look like the landscape of Mars. Red rocks on red sand. Only looking at the wooden wall or door behind it, and the shape of the rock itself, indicates that they are the same tanks.

Note which ones are more popular. :)

Even allowing for this variation I like the last one by a considerable margin. A rock feature should, imho, be massive. And that one hits that "golden rule" point just about exactly. Especially given your proposed planting and stock list this could be a very Amano-like tank.
 
first and last pic look the best.
I think i like five the best and it would make a nics breeding habitat for a cave dweller
 
I like 1 for visual interest, but think if you put the piece on the left in arrangement 4 on the right side of arrangement 5, you'd have a winner.
 
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