I need a collection of human pathways. I have seen that NCI PahtwayInteractionDatabase integrates BioCarta, Reactome and Nature-Curated pathways. It looks like a good resource, but I've never used it and I'm not sure it is comprehensive.
On the other hand, I know KEGG (and its drawbacks) quite well.
I think the question will eventually boil down to in what format you need the pathway information and what are you going to do with it; but if we put these concerns aside, I suggest you use Pathway Commons 2, where multiple data sources such as NCI PID, Reactome, Phosphosite Plus, Panther and so on are being normalized and merged in a nice way. On the home page you will find a few tools that will facilitate your access to this resource or you can use the webservices to extract what you need:
As a side note: NCI PID is going through a re-planning period and although it contains some parts of the Reactome, they are really old; whereas on PC2, you will get the whole up-to-date Reactome data.
Disclaimer: I am a PC developer and somewhat self-promoting here -- but for a good reason :)
