The main pro with keeping your dynamic URL would be that you are saved all the effort that would go along with changing to a static URL. Another good point would be that Google, one of the four leading search engines, has lately stated that they can now effectively crawl and index dynamic URLs.

A con that is associated with dynamic URLs is that they have a much lower clickthrough rate that static URLs. The reason for this is that a static URL is a lot easier for users to read. Also, the chance of the end part of the dynamic URL getting cut off when copy and pasting is very high. This will result is a error when trying to access the webpage. Both of these cons greatly affect your website traffic.

Other cons include the fact that dynamic URLs are basically impossible to remember. You also cannot use them on business cards or any other forms of print marketing. This is another way that it prevents you from directing more traffic to your website.

There is also less keyword relevance or prominence in a dynamic URL than there is in a static URL. Also, if the dynamic URL is used as an anchor text then it will not help with SEO much.

It is important to note that while search engines can now crawl through and index these dynamic URLs, static URLs can still result in better Search Engine Optimization (SEO). Static, keyword rich URLs would result in more frequent and better rankings with search engines. While it can be quite a time-consuming task to rewrite your dynamic URLs, it can definitely prove worth it in the end.