Check the equipment forum sticky on mash tun size.
As I understand it, no sparge and batch sparge need more equipment space. Fly is supposedly the most space effecient.
If you're doing ten gallon batches, I'd reccomend fly sparge.
This is somewhat true, however; no sparge is the only option that requires a larger mash tun space for it to be done by the book. Since everything goes in the tun before you vorlauf and dump you need the extra mash tun space. Batch sparging does not require extra space in your tun, but does require you to have a HLT at temperature to apply the sparge water after you have drained your kettle the first, and then again after your second if you are double batch sparging.
Example for batch sparge; 12 gallon batch you vorlauf and transfer your mash tun to boil kettle, fill with half (if doing a double batch sparge) or all of your sparge water (if doing a single batch sparge... which might require a larger mash tun to accomplish depending on your initial mash thickness), stir and vorlauf and then transfer into kettle. The only difference is if you do a double or single here.
Fly sparging, requires a inch or two of water on top of the grain at all times during the sparge and you measure your kettle volume to know when to stop... or your gravity of runnings if you are worried about over-sparging (which due to efficiency may or may not be more or less than you want in your kettle).
I do a hybrid batch sparge sometimes. This means I am not as worried about my run-off gravity as much as my run-off volume. I do this two ways. 1st, I do a typical batch sparge and dump my first mash run-off into my kettle and completely empty my tun before adding my sparge water (which in a hybrid setup I do until I am a inc or two above my grain bed), stirring and vorlaufing. In a hybrid setup, I know what sparge water I have left in my HLT and start to add that while emptying the sparge from the mash tun. Once I am out of HLT sparge water, the mash tun starts to drop until I am empty (just like you would do for each step in a typical batch sparge). If I am over or under efficiency, it is much easier for me to know where to tweek my software for the next brewday, since my volumes are the same every time.
I agree that you should fret too much about your efficiency. If you get your system down, get repeatable results, then you are well on your way to tweeking things to get to where you want/need to be no matter how you sparge. So, at this point if you got 60% efficiency every time you brew... you know that without making recipe adjustments (or other adjustments) you will get the same results, making it much easier to formulate a recipe based on your system. I would take a repeatable 60% over a fluctuating 75-80% any day!