The answer is largely "it depends". Whatever bank you choose to use may offer different rates for the HELOC vs. the Home Equity loan. A HELOC is more likely to be variable. Interest only loans may or may not be an option depending on your bank.
If you know the loan amount you need and want to lock in the lowest rate possible, then the loan is probably a better option. If you want flexibility at the risk of higher rates, then the HELOC is better.
I personally have a HELOC. I used it for down payments on rental properties, so the flexibility to get extra cash when I needed it was exactly what I signed up for.