Seemed decently smooth to me, no real stuttering some have reported, though perhaps it didn't run at 90 fps and only 60 (by this I mean I don't know what frame rate it ran at, I didn't have stats enabled, I've disabled overlays after I found they degraded performance in certain games like Doom Eternal, I'm not saying it somehow got locked to 60 for me when I tried to do nothing of the sort, but I'm saying maybe it's possible it did not run optimally yet) I didn't notice yet from the excitement and other issues. It has other things that annoy me. Like how there's a separate controls screen for each device like it expects you to use either one or another, either keyboard and mouse, or a flight stick or a gamepad, or whatever. I don't have a full hotas yet myself so I want to use the flight stick with my keyboard in place of a throttle piece, using the stick inputs for basic flight combat stuff and the keyboard for throttle and targeting and all other functions. Basically what I do so far in all such games, from Freespace 2 to MS Flight Simulator to MechWarrior 4; Mercenaries, they all do combinations well.
Ideally there would be one controls screen and you'd set input from any device you desired separately for each function. Then the game would report that function itself in the relevant messages (including duplicates from diff devices). Instead since it thought I only want to use a flight stick it kept asking me to press button 11 or whatever crap those defaulted to (buttons on the stick's base, not reachable with one hand unless you let go of the stick) when for that stuff I wanted to use a keyboard key instead, it wouldn't accept that input until I pressed that button 11 (even though I'm pretty sure I pressed the keyboard equivalent of that function as I had set it, but perhaps the next point ties into this, maybe it hadn't saved that properly after all so I didn't press the right key).
I think there may be issues with controls resetting or not saving right after customizing or perhaps not saving between the game switching to a different device as default or something cos I had to switch my roll and yaw axis three times before it finally worked as I wanted it to. Still all things considered multiple devices do work in combination so after you learn the controls by heart and get past the tutorials there should be no issues, if it does save properly.
Also I first started it up out of VR and changed it to fullscreen display, then I saw it doesn't really let you mess with settings in detail before starting it but only has some basic options and throws you right in the game so I wanted to experience that in VR so switched to VR and then it just wouldn't work, it just kept minimizing the game on the desktop and when it was like that the VR picture was blank until I brought it back up and it kept doing this lol. So I started it out of VR again, changed it back to borderless and then it did this once with the SteamVR window popping over it, but after I clicked in the game again it stayed good.
Edit: and someone in another forum said that I'm right in that controls reset when switching devices so I guess currently it's unplayable for me as I need custom settings for both my devices and to use them in tandem but until that's patched I can't do that except with the default controls which I don't like. Idk why devs of this sort of game have so much trouble with making control configuration when others managed just fine aeons ago. Like how Ace Combat 7 doesn't even let you configure the controls and only offers presets for specifically supported models of stick/hotas and now this. Just let me set any input on any device.