I was thinking about this last night.
Basically if you had the option (assuming you work roughly 37 1/2 hours a week) of either working a standard 5 day 9 - 5, 30 minutes for lunch week or only working Monday, Tuesday and Wednesday but starting really early, ending really late and working 12 1/2 hours each day, which would you choose?
I think I'd definitely prefer the latter as I tend to waste mornings and evenings before work but if I had 4 full days I'd make much better use of them. My only concern'd be not being able to do anything on those three days. That said, if I could change what the the 3 days I worked each week were to suit my needs, I would definitely go for the latter option.