I wonder what was so wrong with Skype that many abandoned it? Now, i've been told that the enterprise variety is a different product that's way worse, but i use the regular Skype occasionally and it's okay.

Personally, i think that it was best before its many redesigns (e.g. the versions that you could get from sites like http://www.oldversion.com/windows/skype/ at least when they worked), but even nowadays it remains usable and does most of what i'd like for the basic use cases from a chat application, or even for video calls or group calls.

Then again, in my eyes many of these platforms are just reinventions of IRC in some capacity, with the occasional nice feature (e.g. Slack/Discord/... having threads, deep API integration with bots/apps etc.) that gets tacked on.