The 8 gets almost no love compared to the X and Plus (the Plus is apparently even outselling the 8). I'm using it since launch day and still extremely happy with it.
It's more pocketable and easier to use one-handed with a relatively light weight compared to the X and 8 Plus. Also it has a fantastic camera (excellent low light performance) and great speakers. Battery life is decent, nothing spectacular but gets me through the day easily with around 7 hours of usage. It's packed with the same blazing fast A11 chip as the X and 8 Plus.
If the X and the Plus would be the same price as the 8, I'd still go for the 8. Like I said I just love the compact size for comfortable one handed use and the fact that it's so pocket friendly. I use it with my left hand and small things like having to open Control Center by swiping from the top right on the X, compared to just swiping from the bottom would annoy me so much on the X. You could use reachability on the X to reach CC, but it's an extra step and just not very Apple-esque.
There are more things I prefer on the 8 (Plus) compared to the X, but I don't want to turn this into a '8Plus is so much better than X' discussion.
If you miss the lighter one handed use, I'd say definitely return the X for the 8. You won't regret it.