Kesab,
Just for your information, a PhD does not automatically entitle you to the EB-1 category (see criteria below). I have a PhD and my lawyer recommended EB-2 because it was so difficult to prove to USCIS that you were 'extraordinary'. Sometimes they set the bar low, sometimes high, depending on the adjudicating officer.
EB-1 allows you to skip the labor cert process but as you have a labor certification you will not be saving any time going for EB-1.
The only other consideration is the availability of a visa number if you petition is approved. A handful of countries have a backlog and applying for a higher category may mean that your date becomes current earlier. I am not sure if EB-2 has a backlog because I wasn't in that situation.
Just my $0.02 worth
An alien’s “extraordinary ability” in the arts, sciences, business, education, or athletics must be demonstrated by sustained national or international acclaim. His or her achievements must be recognized through extensive documentation in the field, and must represent a level of expertise reached by only a small percentage of people at the very top of the field. For example, evidence of the receipt of a major, internationally recognized award – such as a Nobel Prize or Academy Award – will establish EB-1(a) qualification. Alternatively, without such an award, an alien may establish qualification by producing documentation of at least three of the following:
• Receipt of a lesser nationally – not necessarily United States – or internationally recognized prize or award for excellence in the field;
• Membership in associations in the field that require outstanding achievements by their members;
• Published material in a professional or major trade publication, or in the major media, related to the alien or the alien’s work in the field, or scholarly articles in the field written by the alien and published in a professional journal or in the major media;
• A judicial role – individually or as part of a panel – over the work of others in the field;
• Original scientific, scholarly, or artistic contributions of major significance;
• Display of the alien’s work at artistic exhibitions or showcases;
• Performance of a leading or indispensable role for organizations or establishments with distinguished reputations;
• Past command of a high salary, or other significantly high remuneration, for services performed in the field; or
• Commercial successes in the performing arts.