The 780Ti is a better gaming GPU than the Titan when you consider price/performance. I will say there is a HUGE reason you and everyone else should consider purchasing an Nvidia card. It's actually the most long overdue advancement in the history of gaming.
G-Sync.
This little device synchronizes the refresh rate of your monitor to the GPU, rather than your GPU conforming with your monitor's controller. Nvidia is the only GPU manufacturer with access to this technology right now. They may decide to license it in the future, but for now it remains an Nvidia exclusive feature supported by 650Ti and higher Kepler GPUs. I have a pair of GTX660 cards in SLI and I cannot WAIT to get a g-sync monitor. Right now, since FFXIV doesn't play well with adaptive v-sync, my FPS usually goes something like 60, 30, or 20 fps. The reason it drops in those increments is just the inherent nature of synchronizing the GPU to the monitor controller's refresh rate. The GPU will do everything it can to eliminate screen tear. Everything you need to know about vsync is here:
http://hardforum.com/showthread.php?t=928593. More info on G-Sync is here:
http://www.geforce.com/hardware/technology/g-sync/faq.
This is the killer app that Nvidia needed. As intriguing as AMD's Mantle API is, it needs to be actively utilized by developers in order for games to capitalize on the rendering benefits it provides. Nvidia's new tech is passive and its effects are immediately realized with no additional effort required by developers.