Personally, I'd go with the higher processor spec. RAM is always easy to upgrade on a laptop, if you ever feel like needing to. 8gb should be fine for most tasks though.
Performance wise, you'll notice the best boost with a good SSD hard drive. The other two have a combo of both, or a hybird SShd. Basically on the SSHD drives, there is a small portion of ''Solid State'' which cache frequently used applications etc, so loading times are quicker - but it's not true SSD.
With my laptop, I got one with a pure SSD and then bought an external HDD for 50 quid to increase my storage.