For some reason I couldn't find 3dmark Vantage scores for the 750 Ti, nor could I find Fire Strike scores for the Intel HD 2500, so some extrapolation is necessary.
For a little more insight, here are some synthetic benchmarks.
http://www.3dmark.com/3dmv/3757434 Intel HD 2000 3dmark Vantage "free" p1676
http://www.3dmark.com/3dmv/5158294 GT 730 3dmark Vantage p6165
And some more. These are not directly comparable to the ones above, but we'll have to make do.
http://www.3dmark.com/fs/3595098 Geforce 730 Fire Strike 1816
http://www.3dmark.com/fs/2291937 Geforce 750 Ti Fire Strike 3937
So we can see that the 730 is about 4 times faster than the HD 2000, but the 750 Ti is more than twice the speed of the 730, or more than eight times faster than the HD 2000.
So I guess it depends on your tolerance for low frame rates, how much money you have and what 730s and 750 TI's are going for in your region.