These are lessons from my own experience, not tax advice. Talk to a tax professional about your situation.
I originally set up 📝BrightZen Systems as a California C-Corp when there was a "tax promotion" that said if you started a C-Corp during this window you wouldn't have any capital gains tax when you sold it (Qualified Small Business Exemption - "QSB"). Later in the corporation's life, I decided to have it taxed as a subchapter S, which ended up making it not a QSB.
Since then I've learned a few things about the advantages and disadvantages of each setup.
An advantage of the LLC is that single-member LLCs don't need to file separate taxes. However, the disadvantage is that all of the business activity of the LLC ends up going transparently onto Schedule C of your tax return.
The biggest advantage I've found of separating investing (and consulting) into a C-Corp is that if you invest in convertible notes and hard money loans (which is what I usually do), then the C-Corp's business is lending, and loan losses are an operating loss. That pushes through to your 1040 as a reduction in current income, as opposed to a capital loss, which would end up as a deduction against future long-term capital gains. (This may also be an advantage of an LLC; I'm not sure.)
There's also a revenue tax on the S-Corp that I generally try to avoid by transferring stock out of the C-Corp when or if the convertible notes convert to stock.
There are some payroll tax differences as well, but I don't know them well enough to comment on them.