Going to cross post this, as I see another asking similar...
For length of service and fit, go with GM. That is, IF they are still available. Not many seals are anymore. Quite a few posts on here with the part numbers, just plug them into google and if GM still has them, you will find places selling them. The price is worth it. Buying certain parts based on price is a poor way to make a decision, weatherstripping is one of them.
For seals that aren't available anymore, a crapshoot as far as I've seen, but if there is a vendor here, I'd patronize/suggest them solely for being involved with CK5. Typically if the parts are junk, you will know about it here.