This question comes up a lot. I guess because I used to get options that not only had more complicated tax treatment, but the way they were taxed changed during my working time. RSUs are simple as pie. Yes, I get RSUs now and yes, I sell them as absolutely soon as they have been released.
When RSUs are RELEASED (not vested), they are the employer giving you 100% taxable income. Period. The end. There is NO way to get favorable or different tax treatment. Sure, you can have shares with held to use towards tax, but that's simple some of the income given directly to Uncle Sam, just like some of your regular pay is given to Uncle Sam.
There is NO reason to not immediately sell the RSUs upon their release. None. You save zero tax by holding them for 30 days or 30 years. You owe the income tax regardless. Sell them and THEN, you can ask yourself......Do I want to buy my company's stock? If you do, take the money and go to Schwab and transfer that money over and buy however many shares of stock you want to. Because the company gave you taxable income money in the form of stock.