Initially I used just after using a new OnePlus 8 Pro and was left a little disappointed, it appeared to lag a little in places, but using for a few hours straight without any other phone it seemed how I expected it to be, quick in most places, a little lag on occasion, but nothing major and enjoyable to use, nice big screen, loud dual speakers etc..
I had to remind myself it only cost £250 for an 8GB/256GB phone with top specs. It should be faster/smoother for the specs but it's likely down to software which updates can improve on.
It's definitely not slow, and for the money it's the by far the best I've used. I was really tempted to get one myself (or the bigger brother the F3 for £350).
The only thing stopping me getting the same model myself is the max brightness, I generally like really bright displays, but for most uses its plenty bright.