Some site builders, such as Squarespace, Strikingly, Virb, and uKit, restrict you to placing page objects in spots that won't make your site look garish, which can be an advantage if design isn't your forte. Other builders offer more freedom; if that's what you're looking for, check out Gator or Wix. Gator in particular strikes a good balance between design freedom and reponsive restrictions.
In all Website Builder plans any data transmitted from your site will be encrypted using a SSL (Secure Sockets Layer) certificate. Your SSL will establish an encrypted link between your web server and the browser of the person visiting your site. This means that all data will be kept private; which is important if you want visitors to your site to be safe. If you want to sell products or services in your store, you will want to have a SSL since it protects credit card and bank numbers from being intercepted by hackers.