Hello dears,

I have been thinking of using Google's webmasters tool for my websites. However, to verify as site owner I need to download an html & upload to my site.
Wanted to know if adding the html has any short-term or long term drawbacks.
Please share your experience.

HI.
Google webmaster tool helps in checking the duplicate title and duplicate description. It uses sitemap which helps Google to index the pages easily. Moreover it allows you to see all the inbound links.

There are no drawbacks for uploading an HTML file. There are other verification methods  available. Its all upto you as to which method suits you best.
In general, if you have direct access to your server you may find it easier to upload an HTML file.
Here's an interesting knol which might help you in this matter,
http://knol.google.com/k/google-webmaster-tools-verification#Which_method_should_I_use_(2D)_meta_tag(2C)_HTML(2C)_DNS_or_Analytics_code(3F)

Google webmaster tool is very effective for checking indexing status and optimize visibility of your sites and we can make our websites easily Google friendly using Google webmaster tool. It provides
1)   Find errors while crawling your sites.
2)   View website pages on Google index.
3)   Analyze search data
4)   Checking links to your site
5)   Tell Google of your websites
6)   Set the preferred domain for how the URL displayed in SERPs.

Never been good as anyone I guess especially now that they have launched their Panda, many sites owner got threaten to this algorithm.

Webmaster tools is good to use, most important thing why I use it is to check for non-found urls that google wants to crawl . It also gives you good information about sites linking to your site.

Google webmaster tool is very effective to to track your website errors. It has lots of things that you can get for your site and all the needy details about your site. It's allow your to upload robots.txt, also allow to upload sitemap.

HI.
Google webmaster tool keep an eye on the duplicate content and help Google to index the pages easily. Google webmaster is very effective to use.

HI.
Google webmasters is the best way to track the sites and it helps Google to index the page because Webmaster check the duplicate contents and errors after this Google index the site.

Google webmaster tool is very effective for checking indexing status and optimize visibility of your sites and we can make our websites easily Google friendly using Google webmaster tool. It provides
1)   Find errors while crawling your sites.
2)   View website pages on Google index.
3)   Analyze search data
4)   Checking links to your site
5)   Tell Google of your websites
6)   Set the preferred domain for how the URL displayed in SERPs.

Google webmaster tool is really SEO friendly and give you lots of information about your site. It will help you track your problems and error in your site and help you to solve it.