I formed an LLC for a partnership by filling out the state forms and using some templates I found online for the required documents (Articles of Organization, Formation Agreement, Operating Agreement, Power of Attorney, etc.). It really was not complicated, no regrets on doing it on our own. Fortunately our LLC was never "tested" by being sued or anything, so I can only assume that it would have survived attempts to pierce the corporate veil and such.
Speaking of piercing the corporate veil, you probably already know all this already but be certain to open separate bank or credit accounts for your business and use only those, never your personal accounts. Don't do anything as yourself, always maintain sufficient arms-length separation. For example, ONLY pay expenses using the business checking account; keep meticulous records for everything; sign everything as "Dude, Managing Partner, The Dude LLC" not just as "Dude"; when you pay yourself do so as the corporate entity from the business accounts with records to document everything; and so on.
One drawback I discovered since I was operating a real estate investment partnership is that banks will not allow a new, small business to hold a mortgage. We had to put the property mortgages in our own names, which could have exposed us personally, to a degree, if something had gone horribly wrong. I know no way around this until you become a large enough, established business with tons of assets and capital and proven track record before the bank will be willing to issue a mortgage to the LLC.
