Very fun, even for solo players. It's not just Outbreak or a reskinned Siege as a lot of people are lying about, it's more. Unique gadgets, insane amounts of lore, varied abilities for a chunk of the ops (Jager's ADS now attacks enemies, Chanka has his turret, etc.) and every op ability can be upgraded and enhanced.
Worst thing about R6E is the limitation of upgrades to abilities. There's no options or choices, just a single tree that you level up by leveling up the character.
Best thing about R6E is the different feel for every game you play, even if it's on the same map and the same level. You start off at the last sub-level you completed if you do the same level back to back with a new set of missions for each sub-level, ranging from rescuing a VIP (hostage), applying sensors to a nests or taking out a hard Archaen.