Office 365 Enterprise, especially OneDrive for Business. I feel like an unwilling beta tester.
My question for you as a founder is, how else would you prefer that a product introduce new features? I want to make sure that our users don't feel like you do, but I also need to roll out new functions as we grow so there has to be a balance there,
Microsoft had already considered OneDrive for Business (SkyDrive Pro at the time) a finished product. Two years of hell has proven otherwise. Personally I still view OneDrive as an MVP, though I will concede it has gotten a little better over time.
Microsoft has also failed to provide notification of a new feature rolling out several times, causing confusion with end-users. At best, I'll get a brief message in the Office 365 admin portal that says "Within the next 4 months, we'll be rolling out x, y, and z features." I'm glad that I know months in advance of a new feature, but not knowing any type of specific time frame really puts us at a disadvantage.
New features are awesome and I am more than willing to try them out if I know they're still not totally ready. Ultimately what really irritates me is when companies tout a product as "enterprise-ready" that is still riddled with bugs.