I've done quite some mapping work now and I only use copypaste, sometimes not even planting a single tile or wall by hand. However, I strongly beenfit from Lexx' tiled mapper you'll find here on the forum somewhere, along with a custom urban preset made for that, allowing me to draw a street network on a checkerboard and then have it tiled out in a matter of seconds. The first time I go into the actual mapper, I copypaste from a desert template I made to make all the desert parts look work.
Copypaste in itself doesn't mean repition, you just have to do it properly. With only so we tiles and walls available for each use, you HAVE to get away with a lot of repition anyway. I also noticed that as soon as I started mapping, I looked at maps differently ingame and kept spotting a lot of "bugs" on 2238 maps that I would have fixed. The average player who doesn't even know how the mapper works wont be able to see anything.