I think Pocket is better, by the style, fluency, and because it transforms websites to text better than Ip. But, one of the best features of Instapaper (which doesn't have Pocket) is that you can change the title names. I really like that feature.
Definitely Instapaper. I like the design better, pagination mode in the Pocket iOS app ist just plain buggy, and I already used Instapaper back before Pocket (formerly ReadItLater) even existed..
Instapaper has a dark-themed web version which I like and use a lot. Also Instapaper Premium, which I happily paid for a while, is now available for free for all Instapaper users, which should be consider an advantage.
However, I'm using Instapaper for a long while which is the primary reason keep using it.
Night mode is nice, and Pocket has it also. Interestingly, they also have advanced font/formatting features as part of their Pro offering. I don’t know if any other apps where advanced formatting options are part of a premium package.
I only save full page with Evernote (which is the default when you save using their clipper). Means I have it offline and available if the page changes. If it's something where I want it to update I'll bookmark instead in my browser.