Frames do have a lot of important disadvantages. First not all browsers can render frames. You will have to make two sites, one with frames and one without them. Or even three if you are considering a text only version too for text oriented browsers. This means a lot of extra work.
Some browsers seem to crash on frames.
If this happens more than once on the same site, the visitor is likely to never return. Setting up navigation with frames may seem easy at first sight. You will have to include menu's on that page. At least a link to your home page and probably some links to related pages on the site. If you don't your page will be a dead end, a near mortal sin in web design.