The biggest impacts tend to fall around tax treatment. As mentioned above, declaring a Section 83(b) election allows you to declare your RSA as income at the time you receive it. If you choose to declare an 83(b) election, you won't pay taxes when the shares vest later on; instead, you'll pay capital gains tax when you sell the shares down the line.
The idea behind a Section 83(b) election is to minimize total tax liability if you expect company shares to increase over the long run. Getting your tax obligations out of the way early can be a smart move, although it can also be a failing strategy if the company ends up collapsing or if you change jobs before the stock vests.
Whether a Section 83(b) election makes sense depends on your individual circumstances, so be sure to consult with a trusted professional, like a CPA, if you're unsure of how to proceed.