Not really no, a OCed GTX 780 easily outperforms a Titan but has less Cuda cores and 3GB of video memory instead of 6GB, 3 is still a lot though and 6 is only useful on extreme resolutions/Multi-display gaming
The Titan is absolutely the fastest single card you can buy. An overclocked GTX 780 can beat a Titan by a few percent, but of course, a Titan can also be overclocked. Still a GTX 780 with a nice custom design and cooler is a better option for a single monitor, mainly due to cost and customization options.
the 780 is amazing for the money but early titans are by far the fastest single gpu cards without voltage limits and once water blocked can be pushed 30% higher in synthetic tests or roughly 15% faster in synthetics than a water blocked 780.