If you ever want to take VC/angel money, you will most probably need to spend more to restructure and re-incorporate. The boilerplate that services like LegalZoom are not made for startups. They may be fine for other types of businesses, but not for startups. If you're one or two people running a small business, you should be fine.
Even YC advises against incorporating using generic paperwork (I would imagine the YC paperwork is pretty similar to what other Silicon Valley startup attorneys would use):
"Don't incorporate, though, if you can avoid it. It's easier to start with our paperwork than to transfer an existing LLC or S-Corp to a C-Corp."[1]
"Don't incorporate, though, if you can avoid it. It's easier to start with [YC's] paperwork than to transfer an existing LLC or S-Corp to a C-Corp."
YC uses Goodwin Procter for their startup formations [1]. Goodwin Procter not only makes their startup formation documents freely available, they give you an automated service for customizing their boilerplate: http://www.goodwinfoundersworkbench.com/document-driver/
You can create a C Corp with legalzoom. That said, at my last company we incorporated in delaware with the Company Corporation and had to spend about $10k when we raised our series a on restructuring all that and documenting things.
Even YC advises against incorporating using generic paperwork (I would imagine the YC paperwork is pretty similar to what other Silicon Valley startup attorneys would use):
"Don't incorporate, though, if you can avoid it. It's easier to start with our paperwork than to transfer an existing LLC or S-Corp to a C-Corp."[1]
[1] http://ycombinator.com/faq.html