either is fine, only upside is your more likely to get people to link to your html sitemap than your xml sitemap (which is meant for bots not humans).
HTML sitemap is only for user and its provided by website owners for providing proper navigation to the visitors or customers. It doesn't pass any SEO juice and lot of websites don't have any HTML sitemap at all. For proper navigation purpose only it is used in websites.
HTML sitemaps are designed for the user to help them find content on the page. Html site map symbolizes more useful information to the visitors outlining which link is updated where.
sitemaps are essential to getting search engine spiders to search, index and rank the content of your site. It is a single page on the site, which provides the structure of the site by listing its Links, Hierarchy, and Sections. HTML sitemaps are used for the look of the website.
HTML sitemaps are used for the website visitors to help them out for the easy finding of what is present on the site.
Sitemap that help the site users or visitors to easily navigate through the site is the httml sitemap. Where as XML sitemap is specifically for the search engine crawlers to assist in crawling the site.
HTML Sitemap completely about User-Friendly. It won't help you in SEO. this one is proper navigation t0 user land the particular page in easily.