If you plan on using your dslr as a glorified point and shoot, go with the 250D.
If you plan on learning to shoot, using M Av or Tv modes, plan on using more than the center AF point, get the 80D.
Among other things, the rear dial and joystick are THE features that I can’t live without. And, if you need to switch settings on the fly, they’re indispensable.
But, if you don’t plan to learn some shooting, and only want to use the full auto or scene modes, then you wouldn’t be using these features anyway.
Sensor tech is cool and all but when comparing different grades of camera, look at whether or not you’ll be using the features that come with that grade.
From OP: This was quite interesting for me. I've assumed you're implying the additional dials are very advantageous as they allow you to avoid going through the screen / menu options to achieve the same thing making it much more likely you'll make good use of them.
The joystick allows for very quick AF point adjustment. Simply push it in a direction and boom, new point selected. On an XXXD, one must first hit the AF Select button and then spin the dial until you wind up at the chosen point. Doing this for a portrait isn't the end of the world - doing it for action/wildlife/anything moving will really cramp your style.
But, again, this assumes that you intentionally set AF points - something many beginner shooters don't bother with. If you don't need the feature, why pay for it?
The rear dial is much the same. In M mode, it allows for your shutter speed options to be on one dial and aperture on the other, allowing you to adjust both at the same time. Again, if shooting stationary objects, it's no real loss. If shooting moving subjects in changing light, it's a real benefit.
In Av or Tv modes, your main dial adjusts the chosen aperture/shutter speed while the other adjusts exposure compensation. Again, super useful.
The ergonomics and handling of the XXD and XD series are far and away better than the XXXD series...but they're also targeted toward people that know how to use a camera and will want to adjust those settings. There are many people that simply want a camera and never move off the green box mode and think that dial is simply there for menu navigation. For those, the XXXD is the winner.
I mention these points because, to me, the ability to use a tool easily outweighs almost all other factors.
I would like to take photos of nature (landscapes, mountains, lakes, hiking trails, trees, birds), portrait shots and cityscapes.
The 80D will excel here in shooting the birds. The rest is a toss up. The best gear you can get for landscape is ... drumroll ... not a camera. It's not even a lens. It's a filter.
Every one of your favorite landscape shots from a pro was shot with a polarizer, possibly a neutral density, possibly a graduated neutral density.
My most recent acquisition was a 5Dmk2. Yes, the one from 2008. Yea, camera tech has come a long way since then. But, it meets my needs and I'd rather sink the money into glass - both lenses and filters.
I would like the camera to give me as much control as possible so I can progress from amateur to enthusiast without having to buy another camera.
If you truly do want to go from amateur to enthusiast, go with the 80D. It's the same control layout as every other camera on up the food chain to pro bodies. There's a reason for it.
I'm now leaning favourably towards the second hand 80D. I'm just considering the value at £500.
Camera tech evolves constantly and unless you are a pro needing the latest feature for something, it's likely that you can get by very well with outdated tech. Like I said, I'm still rocking the 5Dmk2 and a 60D on the side (and some film gear to, but that's a different story).
You're better off spending less on an older body and more on better glass than you would be getting a newer body but having to spend less on glass. I can't stress this enough.