I know they are still working on it, but there are still a few problems in my opinion that should be fixed… stuff like viewport speed is significantly slower in production scenes compared to 2.7 making it barely useable… lots of production scenes that were made in 2.7 crash out 2.8… the 2.7 keymap sometimes is lost and the pie menus come back… stuff like that.
Production scenes for us is infrastructure visualisation… so our scenes are sometimes 20km by 20km… much larger then a normal CG scene.
Bugs and crashes you can report in the tracker, other issues you can mention on this forum.
Regarding viewport performance, it matters a lot which operations, which settings are used and the graphics card. In my experience with big scenes, navigating is usually quite a bit faster than 2.7. Where it can be slower is when manipulating objects and particularly editing meshes, where there is still some code that is known to need optimization to get it back to 2.7x level. There may be other unknown issues too though, hard to say without details.
In terms of performance, I just opened one of our production scenes which has trees duplicated on a particle plane, These trees are in bounding box mode. That layer/collection in Blender2.7 was reported as 768 objects compared to around 30,000 in 2.8. This layer is what slowed down the scene.
Graphics card is GTX 1080 and just standard solid mode for playback. We are talking a slowdown from ~12-13fps to 2fps