Not really.
-Ti parts are usually in between the neighboring parts in terms of price and performance, no surprise there.
Thing is, the further up the stack you go, the less additional performance you get per $ spent.
If you plot frame-rates per dollar on a graph, it's usually the midrange parts like the 750 Ti or 760 that are the best deal, and the average gaming enthusiasts out there will generally be willing to spend a little extra for the next step up like a 760 Ti or a 770.
(This might not be 100% exact, since card prices change daily, but you get the idea, right?)
There are definitely other reasons (good and bad) to get a 780/780Ti/Titan, but price/performance isn't typically one of them.
The same applies to the 9xx series, except there's fewer models to choose from (960/970/980. The 980 Ti doesn't exist yet.)