Pipelines spill, leak and spew oil FAR more than the proponents would ever admit, even when the stats and reports are shoved right in their faces.
There are a ton of other hot button issues involved in pipelines too, such as essentially stealing lands to host/build them, the environmental impact of their construction (considerable even if no leak/spill ever happens), etc.
There are plenty of reasons people don't care for them.
But, if one's concern is simply the spill angle and the environmental impact of them, well... pipelines are proven to unleash significantly less oil than trucking, rail or shipping transportation methods when there is a failure or a spill.
The pipeline sensors are not at all as robust or as accurate as the Keystone proponents lie to claim they are... but it's always going to be easier and faster to close off a valve once you've found the leak, than it will be to right a massive capsized oiltanker and plug a hole in its hull, etc.
http://www.huffingtonpost.ca/news/canada-oil-spill/
http://globalnews.ca/news/1699902/al...e-into-muskeg/