Also, "I talked to somebody currently working for this company while they're at their job, and they told me it was great" is not exactly a very reliable way to get data.
Also, who is the boss/supervisor who would fire or penalise the driver for saying it's not great? More importantly, since there no strenuous and expensive licencing going on, it's simple to just stop being an Uber driver if it doesn't suit you.
From the view of the driver it could be you: It's not that uncommon for corporations to test employees like that using HR people disguised as customers. I have no idea whether Uber does that, though.