xml-sitemaps.com will not work for site with larger number of pages and few dynamic url's . g site crawler keeps on crawling my site and it never finishes even if i run it for more that 24 hours
A1 Sitemap Generator will automatically detect e.g. example.com/dir/index.html as duplicate of example.com/dir/ (It is customizable what you want recognized as a duplicate URL.) A1SG also recognizes http redirects, meta redirects, canonical etc. so unless your website is truly flawed with lots of different types of duplicate URLs, it should not be much of a problem
well site map is a waste of time.. you don't need to submit any kind of sitemap .. search engine it self send traffic to your site if you have your own unique cotent
I agreed that Google is very smart and he can crawl pages and give traffic to your website.. But the sitemap helps to crawl each and every individual page in a "short time"!!! In other sense, Sitemap is one of the necessary step of SEO.