From whose perspective?
"Advanced Search Engine" might have the edge, as the perception that they can easily filter/target their search across the thousands or even millions of daters in a given site's database may increase their likelihood to join and/or pay a premium to use the site.
For the dating company:
A "Superior Matching Algorithm", which demonstrably and verifiably resulted in more successful dates/hookups/relationships/marriages (depending on the site's niche/vision) would be a critical technical victory over a field of competitors who do not currently release detailed statistics.
Either way, at least in the near term, it is unlikely that EITHER would produce a significant upheaval in the online dating industry, where advertising dollars spent seems more correlative with marketshare and revenue.
My own opinion is that both are still great goals for a new/smaller online dating company to pursue, as both types of technology could potentially be re-used/licensed outside the dating sphere… But it's likely that some other factor (mobile app, new site niche, security event) will result in greater overall changes to the dating landscape.