I'm going to try to stay unbiased here. Spiderman has his "spider sense" and Vader has the force, so both parties has a way of predicting the future/ sensing danger or what have you. So we can consider them equal there, both have a sort of ranged attack ( Spiderman has his webs, can slingshot rocks or other objects. Vader has the Force, he can also throw objects around.) Spiderman obviously has agility on his side, but that's not to say Vader's a completely immobile, he's got his force jump, speed, and could take more hits from Spidey than Spidey could take from Vader. So far it seems mostly equal if you assume that their ranged attacks are equal, and Spideys speed is equal to Vader's strength. For close-quarters, Vader wins hands down, obviously with his lightsaber, but even without his saber, I believe he would still crush Spidey, he is mostly robot after all. Now let's set some scenarios, let's say in an abandoned building. This would fit Spidey well, using guerilla like tactics, hitting Vader a couple times and then retreating into the shadows or behind walls. Vader would likely start brewing down walls in an attempt to stop this, but I believe this would be Spideys best shot at killing Vader. But on a 1 on 1 environment , mono a mono, flat surfaces, just them in their glory, Vader would win. Considering the reflexes of a Sith, any attempts of face-web-blinding would be laughed away with a flick of Vader's wrist. Spideys only chance would be keeping his distance, but using his web would be less than useless. His only chance would be to get in close, try to disarm him and then proceed, but I believe Vader would best him this situation, and most other situations.