Usually there are very basic templates included for the 'free' website and, alongside, the offer of far
better templates to purchase - aha... a way for the company to make you pay! Basic templates will not give
you a website that looks professional - often the purchased templates do not either!
Websites should display correctly on different browser (eg. IE, Firefox etc.) - many free websites do not.
Building the actual site has confused many very intelligent people. We have had doctors who were completely confused when faced with adding a slideshow to their free website before joining Webgloss. The option was there, 'add a slideshow', but somehow it just wasn't happening! Often there is a 'paid support' option - but then the website is no longer free!
The code behind free websites is generated. Generated code has to allow for hundreds of differing scenarios and so it is 'heavy' code. Heavy code makes your website load slowly. If you are also using their servers to host the website you can be sure that they will also be slow. Your potential clients will not wait for your site to load - they will move on to your competitors' websites instead.
Very little organic SEO is available for free websites. SEO that works is complex and companies giving you free websites are not going to offer this.
Most have included advertisements, either on the website itself or when you 'log in' to control it. Often the advertisements (in the footer of your own website) are for your competitors - great!
Templates. Webgloss hates templates but let's ignore that fact for now. Many of the large companies offering free websites (with TV ads to tell you about them!) show a selection of templates that are so small you cannot see what you are choosing. It certainly isn't a user friendly system!
You usually end up with a website that looks awful. A website that will not get anywhere in Google on its own merit. A website that was not worth the hours of frustration you spent building it with their so called 'easy build' system.