Great points by everyone. Put simply, it depends in your desired outcome as a true startup
If you are looking to get cut through/noticed on merit only, probably not
If you want to meet like minded people, then yes.
If you want a good personal experience, then yes.
I know of a few large companies that are struggling to have their planned presence noticed without significant investment.
The good news is this sort of thing is always cyclical and there is already an event out there that is better for you, and is what SXSW was years ago. Good luck!