Salesforce has been a terrible experience with our company. I'll focus on the customer support / service module since as a sales platform, it definitely shines, but as everything else it falters. Lightning, the "new" experience that kept being touted as the solution to our existing problems, has been even worse -- it is incredibly slow and bloated. I have to restart my browser periodically since it starts taking up 2-4 gigabytes of memory in Chrome. The interface feels like it is stuck in the past, being unable to use native tabs in your browser and forced to use their tab implementation. Everything feels clunky and slow. The API to use things is pretty awful and obtuse; the code for custom components is insanely verbose for the simplest things.

The marketplace is insanely expensive to add simple features or tools that many other platforms have built in -- or, if not built in, easily developed with a sane API. Look at this sample project for a session timer to get a feel for the insanity: https://github.com/SalesforceLabs/CaseTimer and things like a command line interface and source control for your sites are either nonexistent or poorly supported or documented.

The only reason we use it is because the directive came from above; Salesforce feels like Oracle to me in that it gets sold to the higher level execs who never actually use it, and it gets forced on everyone else.

I know there are some good Salesforce sites around somewhere.. but those seem to be the ones where they've replaced all the Salesforce stuff with their own UI and simply use it as a backend database.

I highly recommend avoiding it like the plague.