Through several different posts it has been suggested that the 750Ti might not be capable of crunching yet due to the new Maxwell architecture, but I have been unable to find any definitive answer.  So, after coming home from work today I found that the Easter Bunny (a.k.a. UPS) left me a brand-spanking new EVGA GTX 650Ti Superclocked (p/n: 02G-P4-3753-KR).  This card uses the stock cooler not the ACX cooler.  Drop everything!  Close the shades, lock the doors, turn off the phone, it is time to play with some new hardware!
Okay, I am not a professional reviewer so I will just keep this short and sweet.  I am happy to say that the 750Ti crunches just fine!
I did some quick and dirty time runs against my 680 and 570 and listed the results below.
 
                                             680    570   750Ti
Milkyway Separtation (Modified Fit) 1.30    8:57   4:20   15:03
Milkyway 1.02                               4:29   2:11    7:32
Einstein BRP Search (Arecibo) 1.39         31:00  43:22   51:39
SETI v7 7.00                                7:40   8:23   11:21
 
Time constraints prevented me from running more tests, but if anyone is interested in a specific project just let me know and I will try to run it.  It is interesting to note that in both Milkyway runs the 570 and 750 were utilizing 95-100 percent of the GPU while the 680 hovered around 67 percent.  The 750Ti certainly won't win any speed contests and I'll leave it up to the professionals to determine if it is a good card or not, but for someone on a budget and looking for a modest boost to their crunching performance, the 750Ti could be worth looking into.

Khalifrio
I would like to see how it works with GPU Grid. There has been some people having issues trying to run the 750Ti on GPU Grid.
 
How is the fan noise level with ACX on 750Ti? There has been some complaints its pretty loud. I have been contemplating adding a 750Ti or maybe even two as low cost/low power draw GPU's for crunching. But I have been holding off ordering a EVGA 750Ti because of the noise complaints.

Yes, I wanted to try GPU Grid as well, but held off until I tried some shorter apps first.  I will see about GPU Grid possibly tomorrow or over the weekend.  Collatz is also on the list, although they seem to be down at the moment.
I cannot comment on the noisy ACX cooler issue because mine is not an ACX model.  I run my both my 570 and 680 at about 60% fan speed and I do not notice any change in noise level when I increase the fan speed on the 750.

Ran some more time trials on various projects and here are the updated results:
 
                                               680       570      750Ti
Milkyway Separation (Modified Fit) 1.30       8:57      4:20      15:03
Milkyway 1.02                                 4:29      2:11       7:32
Einstein BRP Search (Arecibo) 1.39           31:00     43:22      51:39
SETI v7 7.00                                  7:40      8:23      11:21
SETI AstroPulse v6 6.04                      32:06     38:28      42:52
PrimeGrid Proth Prime Search (Sieve)          7:39     14:29      29:47
GPU Grid Short Run                         1:51:54   3:15:03    2:50:32
 
While I didn't run every GPU task out there, the good new is that it seems the 750Ti is able to run most if not all of them.  It definitely seems better suited to some projects than others, though.  In both Milkyway and PrimeGrid it was about a quarter of the speed of the faster chip, but made a fair showing in Einstein, SETI and GPU Grid.  In fact, it even beat out my 570 by a fair margin in GPU Grid.  I had hoped to add Colletz to the list but it seems that their servers are still down.
 
Edit:  My only concern was that at times the 750Ti seemed to be running quite a bit hotter than the other two cards, topping 80C while running PrimeGrid.  This could just be because of my install as it sits between my two larger cards, or maybe PrimeGrid simply cause the cards to put out more heat.  I'll swap things around to see if there is any change.

Yes, the 750Ti has a single fan that pushes air in and through a heat sink, from there the hot air basically escapes in all directions.  With my 750 sandwiched between my two larger cards the hot air was probably being recirculated back through the 750.  I swapped the 750 and 570 (from top to bottom it is now 680, 570, 750, RAIDR SSD) and changed some fan placements.  So far the results look promising.  If I feel ambitious I might try Prime Grid again and recheck my temps.
 
BTW, this thing overclocks great!  Boost clock is rated at 1255 MHz.  But I am easily running it at 1500.