Some quick impressions based on 24 hours with the S5e (and how it compares to an iPad Pro)
Lightness and thinness: I have an iPad Pro 11 with a smart folio cover. Compared to the iPad, this is like holding a feather in your hand. I have an inexpensive felt cover for the S5e so the whole package is much more conducive to one-handed use. Great for casual sofa browsing. The weight of the S5e is right in the middle of the iPad Pro and an iPad mini.
Screen: Wow - the AMOLED screen is stunning, with amazing colours, black blacks and ridiculous brightness. It lacks 120Hz Pro motion like on the iPad, obviously, but it's easily forgivable for the price and the fact you're getting Samsung's best OLED screen.
Performance: It's clearly mid-tier in terms of overall speed, fluidity etc. It's mostly quick and smooth in general operation but there are some frame-rate drops if you do lots of opening and closing of apps in quick succession - like it's swapping stuff in and out of RAM. But generally, when you're just using YouTube, Chrome, Gmail etc it's responsive and smooth. Of course, it's no iPad Pro when it comes to that feeling of manipulating the pixels with your fingers but that's to be expected.
First impressions are that I really like it, as it's much more 'handleable' on the sofa and in bed. It's not that the Pro is huge and unwieldy, but the smaller size and weight of the S5e just tips it into that area that's closer to an iPad mini sized device.
Its big USP over any iPad is the AMOLED screen - it's gorgeous to look at. If you spend lots of time in Youtube and watching movies then the screen is worth the price alone.