- Relevance of results on the SERP to a user's queries.
- The time it takes to load homepage of a search engine.
- The time it takes to load the SERP of a search engine.
- The comprehensiveness of a search engine's index.
- The time it takes for a freshly submitted URL to be indexed by a search engine (Currently not applicable in case of AOL Search & Ask.com Search Engine).
- The visual appeal of both the homepage and SERP of a search engine (My current favorite is Live Search).
- The ease-of-use & intuitiveness of user interface of a search engine (This is not the same as visual appeal).
- The amount of advertising (including self-promotional links) shown on homepage as well as on a SERP.
- The relevance of ads shown on a SERP to a user's queries.
- The features & tools that a search engine provides to a user.
I have concluded from my today's test of the top 5 Web search engines that Microsoft's Live Search is now better (for daily or general use) than Ask.com Search Engine. In fact Live Search is now so good that it does the job about 75% of the time (For me). Only about 25% of the time do I have to switch to Google or Yahoo! Search to get useful results. I wish to add that till some months back, it was Ask.com Search Engine which was better than Live Search. I also want to add that I do not wish to imply that Live Search has gotten better than Ask.com Search Engine today. Rather it's me who has concluded this now by way of the test I conducted today.
Finally, I wish to add that Live Search's working for me about 75% of the time (assuming Google is given 100% on the comparison scale) does not mean that Live Search has started giving good enough results about 75% of the time in general, or 'for everybody' (i.e. Live Search is as good as Google for every 3 out of 4 queries, on average). It's only for my set of queries that Live Search fares this good. For a different set of queries, Live Search will surely get a different score. Nevertheless, Live Search has improved dramatically. That's beyond doubt.