It's quick to add videos into your website and it works well with responsive design so you don't have problems when resizing windows or changing resolutions! Also there is an option in settings that allows users without JavaScript enabled (which I think should be default) but if not then at least give them options as some websites just won’t work properly unless they use JS - which can sometimes cause issues depending upon what kind of site/website its used within.
Sometimes adding large files takes longer than i would like too due to slow internet speeds etc., especially over mobile networks where speed isn't great either unfortunately :( however once added this doesn't usually seem laggy or glitchy afterwards though, maybe try out different file sizes? If someone wants smooth transitions between pages while using embedded YouTube movies we recommend getting fitvidjs installed onto their sites first before uploading any media themselves because otherwise things tend get buggy after awhile :).