I really like your enviroments. 75 x 50 cm!! That's one heck of a big cityscape-drawing. The buildings appear to be drawn by hand, without the use of a ruler. Is that correct? I like it, gives the city a lively impression, but I would be careful, to not make the lines to briskly, or I might take away from the architectural side of the buidlings.
I agree with the last two being more interesting, because of the perspective. They have more tension, than the cityscape, though, if one likes to get lost in sch cityscapes, I bet he loves the first one. There's so much to look at, in that one - just lacks tiny ppl teeming around.