We have just achieved PR4 from PR1 for our site www.buzzerhut.com , will it add value to our website ? will it effect our search engine ranking etc ?
It may increase the value of your site slightly. It will affect your SE rankings only if you do the right things to get your pages ranked.
yes offcourse its a +ve sign for you also we should not misunderstand the PR with rankings. Rankings and PR is different but its a helping factor for website SERPS. PR is the compatibility of the webpage or website has per the Google guidelines. Google has certain factors to rank the webpage, if the webpage/website met those, Google ranks those pages higher PR. PR is also depend on the traffic, i released that the website getting high traffic from search engine build up the PR very soon. I have optimizated many new website which had no traffic earlier from the search engine but after that it started getting rankings > traffic > then PR.
PR does not depend on traffic. PR is built one way and one way only and that is with links. You do not get PR any other way. If you get high traffic from search engines, then you did well with seo and rankings, not because your PR is good and you will not gain PR from traffic. PR is good if you want to sell links on your site, but for the average internet user, it means nothing.