I am not sure what you are expecting to be "faster".
Unlike graphics cards which increase the FPS in a 3d game for example, most of the prosumer audio interfaces don't offer any processing beyond audio a/d conversion (the only real exception would be for certain real time effects such as reverb/compression/eq). Almost all of the "speed" is going to be determined by the speed of your computer. Just like buying a better graphics card isn't going to speed up the time it takes to run a filter in photoshop for example, that is dependant on the system speed.
What you are getting with the Delta1010 are higher quality preamps (though how much higher i don't know. the mobilepre had decent preamps i thought). You are also getting more preamps, as well as MIDI, digital inputs...etc.
As far as the comment of PCI being higher quality than firewire/USB - i would have to say that is not true. Look at systems like the Digi002 that are firewire. Firewire is superior to USB for audio uses becuase of the sustained transfer rates...but honestly PCI isn't in and of itself an "upgrade".
The Delta1010 is and has always been a pretty nice unit. Personally I would look at a Presonus Firepod which has the same types of features. Higher quality preamps....but, just something to look at.
The point of my post is: with an upgrade from your mobilepre, you should expect a slightly better sound quality with less noise but this will also depend on your mics. In terms of the overall speed of work - that's about the computer not the card. So unless you really need the extra inputs at this time you might want to examine the rest of your system first. For example, what are you using for monitors?
Many people starting out get into an interface and start itching for more, a way to get better recordings...etc - and immediately want to upgrade interfaces. However a good pair of nearfield monitors will do more for the quality of your mixes and the "feel" of the system than just about anything else.
-Wes
