I don't think the border hurts in any way; I'm not sure it helps, but like the colour and style of a frame one would choose, it's a very personal thing.
C&C per req:
1. Nice, good composition, however would prefer it if the first light standaard, image left was cropped. While early morning light is good, this one might have been just a bit too early. The use a circular polarizer (CPOL) would have really added oomph to the sky.
2. Classic! Well done; again a CPOL would have really helped. This image needs a little work however; the shadows on the right faces are just a bit too dark. This would have been an ideal candidate for an HDR. However a bit of work with adjustment layers should make it pop.
3. Very nice; I imagine the tempation to just scoot over that fence must have been very strong. I think with this one, I would have been tempted to shoot the towers in portrait aspect, and eliminate the brick building image right, and take the perspective to the extreme.
4. Lacks the feeling of the older structures, but fine as-is except for a blown sky.
Just my $00.02 worth - your milage may vary.
~John