I talked a little about my curved screen experience in Finally hooked up my 34" UWQHD monitor! . I’m still enjoying the curved screen as it ‘feels’ more immersive. I know that’s a very subjective metric but I now prefer a curved screen 
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I’m still getting used to laying windows out at this resolution (3440*1440). Splitting the screen between two apps still leaves a lot of dead space in each app. Splitting it evenly between four windows is better but feels a little cramped for the I’m window actively being worked in. KDE’s tiling manager has been helping me figure it. Lately, a three way split of 25/50/25 has fit the bill lately but I’m still working out kinks.
My desktop has to 27” FHD (1920*1080) monitors. My primary monitor is curved. The secondary screen is regular. I definitely prefer the curved.