ok Crotchrocket as the example you have given is B****ks i will be fuller.
I said price comparison
wiggle list an Alfine 11 at £430 and list the shifter at £65, so that is £495 for a hub, two derailleurs, two chainrings, two shifters and a cassette. I trust that makes sense?
Road.cc have an article where they claimed to have weighed the hub and sundries and come to 1744grams, they do mention that Shimano are claiming 1590grams
Now for £500 i can get some fairly high-end kit i think you would agree.
According to wiggle.
XT front mech £35, rear mech £70, Cassette £65, Shifters £100, and the rear hub is £45 Chainrings, as you would be using the middle with the alfine i feel the correct balance is struck by quoting the inner and outer only. So XT inner £15 and outer £80 that comes to a grand total of £410. So i still have £90 to spend.
i could get a far lighter hub than the XT and still be within budget, a few ti and alu bolts. XT chainrings are obscenely expensive TA or Middleburn would be alot cheaper and would let me stretch the budget further.
Now for weight, According to the weights published by Shimano, Front derailleur is 152g, rear 227, cassette 256, shifters 255 and rear hub 411grams. i can't find a chainring weight quoted, but that lot comes in at 1301grams. for arguments sake i will assume two chainrings are around 100grama so yes quoted v actual but still 300grams lighter. and if we look at quote v quote then 200 grams lighter.
So to summarize you can save £90 and save more than 200grams in weight by running an XT drivechain as compared to an Alfine 11.
As i said earlier look at the price and the weight and then make a comparison on that.