I'm not fond of the sky scraper.
I'm not sure if I would use it for scenery. I understand it wouldn't be important in a build as it's more of a towering backdrop or an un-used building, but it just seems to lack detail.
I do like the red building though. I'm not quite sure why though. It does remind me of an old fire brigade building in a "Matchbox" style mini-driving circuit thing that I had when I was younger. I think the colours work really well though.
You should do some more.