I would say that the New Outlook does not work fine and is not ready for mass use. I recognize that not all users care about the same features, but these two things drive me crazy and seem like critical deficiencies. I won't switch from regular Outlook until these are fixed, just tested it again right now to confirm these still don't work:
1. Hitting the menu key on a misspelled word does not bring up spelling fixes (Menu key is the same as right-clicking, which also doesn't work for spelling fixes in New Outlook, but positioned at the keyboard cursor instead of the mouse cursor). This means if I'm typing and misspell a word, see the red underline, I now have to take my hands off the keyboard and reach for the mouse to left click to fix (where it's right-click in every other program including all the other MS Office apps, so even that is inconsistent). That destroys productivity. While writing or typing, most important is to let the user keep hands on the keyboard at all times, meaning supporting the Menu key (Shift+F10 on laptops without the Menu key) for spelling fixes like all other apps do.
2., The folder selection does not respond to touch for scrolling. You can touch scroll the message list, but not the folder list. This means if you have more folders than fit vertically on the window, there's no way to get to them by touch. This also means you can't drag and drop messages into a folder by touch if it's not already on the screen.
Both of these are such fundamental basic features of a mail program, I don't understand how MS can even think it's ready to show Outlook off to users, let alone be ready to replace Outlook or Mail & Calendar.
These problem are in addition to lacking all the power features that make Outlook such a killer app for mail: Rules, macros, complex view options, etc.
On the positive side, I would say that New Outlook looks nice and most other functions work about as you'd accept. It's just not ready yet.