Where keywordkeyword.com has the target word in the domain name where as keyword.keyword has one word in the domain name and one in the tld there will quite obviously be algorithm differences, however slight.
I should have added to my first comment, a keyword may be favored in the domain name rather than as a top level domain.
For those who still live in the old days of seo, be sure to realize that keyword in domain name has very little impact, it is not the same as keyword in url which some seem to be confused about.
As I alluded to earlier, seo is moving towards user experience more than links and keywords. However at this point in time, keywords are still the main thing.
And for the last time... ranking a new domain name on google for a weak keyword does not mean you found the jackpot gtld, when are people going to get the message, ranking is based on so much more than the tld!
Good luck!