Is there drag from a Alfine hub?

I'm debating getting a Genesis Day-one Di2 Alfine to replace my Genesis Croix de fer and Day-one SS.. I just want to know if it will be good as a general alrounder? I love my day-one and commute on it mostly - 10 miles each way with 100ft elevation.. then CDF gets used for the odd commute and then social riding and the odd sportive (800 miles last year)..

Would the Day-one Di2 be a good compromise with the two?

Why do you want to replace two bikes with one?
Alfine bike will be heavier, gear changes are evenly spaced, and will feel odd for a while, as you'll never find that gear that is just right like you can on a normally geared bike, and there will be about half the gears that you never really use.
Replace the SS with the di2 if you want an everyday commuter and keep the cdf for your sportives etc....
Also why di2 and not just common or garden wired alfine? Unless you can get a good deal the jump in price is kinda steep...

Suppose I'm just after a single bike.. CDF doesn't get used that much, I find the day-one nicer to ride than the CDF. Di2 is £680 on cycle to work!! (ex display 2015 model - carbon fork, hydro brakes etc)

Why don't you just put gears on the day one?

I had thought about that, I prob would of if it was the disc model, but it isn't..

All fine except for spotives. Wouldn't do that on an Alfine. Not sure why...but just no.

Cheers, it's not like a do a load of them but have done 100 mile one on the cdf..

Alfine bike will be heavier,

This is probably true, but I suspect the weight penalty is actually pretty minimal and it's just the concentration of the weight in the rear hub that makes it seem significantly heavier.

I don't tend to use my Nexus (basically the same as an alfine 8) in 4th gear as despite being the 'direct drive' gear, I feel thatin this gear there isa bit of drag. I don't notice it in other gears. I've had an Alfine 8 in the past and it felt the same, I suspect there may be a gear in the 11 speed hub that feels similar.

My Day One wears full guards and gets a lot of wet weather use (commuting). It also has a dynamo lighting setup which I feel is probably it's weak spot in the wet. I'm glad it's weak spot only affects the lights and would be cheap to fix. If you see what I mean?

Yeah, thanks for that. I'm not sure there would be much weight difference.. my day-one with rack, guards is up over 12kg.. even ny CDF is 10.3kg without guards.. the alfine day-one is 853 tubing with carbon fork opposed to 725 for the CDF and cro-mo for my current day-one, so frame may be slightly lighter.. to offset it.. yeah I know what you mean about more weight on the back wheel.. AGain the 35mm tyres that come on the day-ones are over 530g each, so you could easily take 200g per wheel off with a tyre..