Yes, about to post the same... Compared to my S8 Oreo the S9+ seems very sluggish in terms of general operations and menus etc. Nice and smooth but a bit frustratingly slow .. Outlook very much so. ..
Not sure if it's because I transferred data via smartswitch .. May try a fresh reset...
I don't know what the S8 was like as I am coming to the S9+ from an S7 Edge, but the S9+ feels noticeably quicker in use and benchmarks well in Geekbench, so performance is good. I just have a problem with stuttering audio playback on mine, which I posted a thread about on here.