We have had pretty good (albeit not perfect) experience with Skype for Business over the last few years. We use it with Office 365 and the Cloud PBX, so we don't have any PBX/POTS or server hardware in our office, and we haven't had many issues with connectivity, especially in the past year or so. The meetings work very well, the PBX functionality works great, presence is a huge plus across all the Office products, and the ability to federate communications and presence with other businesses has been great for our consulting business. And paired with low-cost Polycom phones on the desk, the hardware/software combination is excellent and the value is truly there. It's not without its flaws, though: IMs in particular often get lost when you have multiple devices (i.e. a message goes to your mobile and you don't see it on the desktop), the mobile apps (especially Android) are pretty horrid, and the future of merging with Teams makes things uncertain (although promising).

Yes, it is. They're trying to replace it with Teams, though, which is way better.

Lync was nice and actually worked pretty well. Last time I used Skype for business though, it was like they took out all the parts of Lync that worked well and replaced them with the worst parts of (non-business) Skype.