Wow, 33km each way is 20.5 miles each way. That is a long, long, *long* ways to ride - 40 miles each day.

I personally own a Civia Highland with an Alfine 8 hub and a front dynamo. It's not as fast as my road bike, and it's more work to bike the same distance. I know - I tried it last summer with regular 28c tires. In fact, 50% of the reason I bought a summer commuting bike (and relegated the Civia to winter-only duties) was because it was a slower bike that took more effort to bike places (the other 50% was that a road bike fit into my car, while a bike with straight handlebars did not). To be fair, the bike is also upright handlebars and has a dynamo front hub, but the front dynamo guys would also claim (just like the igh guys) that a loss in efficiency is totally theoretical.

I agree that you sometimes feel like you can't quite get in the right gear with my Alfine, but I'm also not sure it's actually a big deal - I kinda wonder if my legs are just used to certain ratios, and they would adapt to the Alfine's ratios over time. I also never actually had much of a problem with running out of gears - I personally never felt like I needed lower than the low gear or higher than the high gear.

However, after buying on and owning one, if I did it again and wanted low maintenance, I would buy one of the "IGH + Belt Drive" models. I find the supposed "lack of required maintenance" on an IGH with chain to be highly, highly overblown.

Because - an IGH still has a chain. And I own 4 bikes right now (3 derailleur), and after the first 100-300 miles where the cables stretch (and even there, I had to adjust my IGH for cable stretch as well), the derailler itself doesn't have any maintenance. It just keeps working. And if it did need adjustment, it's actually just a little hand-screw thing on the back of the derailler that you spin a little to adjust it - if you learn to do it, the only tools you even use would be that it's easier to do if you have a bike stand to hold the bike off the ground, but that's not "required" just makes it easier. My deraillers just don't seem to go out of adjustment. No, my bikes aren't from target. I don't own any a bike with a derailleur below Tiagra grade. But with adequate components, I'm not "constantly adjusting them". Occasionally they feel like they're not quite perfectly tuned. Imagine my suprised this winter when I got that exact same feeling on my Alfine bike this winter! Seems like I need to check the little cable adjustment thingy on my Alfine again...yeah, it's not making a "click-click-click" noise while I pedal (and you can adjust that by hand on a derailler if it was), but it's just not shifting quite right.

Nearly all the "regular maintenance" on a bike comes from the chain. Which - an IGH bike still has. Oiling the chain. Cleaning the chain. Squeaky chain after it rains. All that stuff that people regularly do maintenance on - is on the chain. And an IGH still has a chain (unless you get one of the cool belt drive models). 2 bikes shops that sell IGH's here thought that the chain would last less long under constant tension on an IGH than it would on a derailler system. So where's the maintenance savings? Even the cassette - and igh only has one cog, while a derailler system has several, but it still wears out just like a cassette on a derailleur system does.

In terms of speed, I don't know that I noticed wind resistance being a problem when there's no wind, but I sure did notice it when I had to bike into the wind. It was a big difference. The road bike lets you get more narrow and the wind doesn't affect you as much. The upright handlebar bike turns you into a giant sail into the wind. I didn't like the effect for 5-10 miles. Going 20 miles...

So, as someone who owns one and regularly rode one last summer, for your kind of distance I would say -
1. It's probably a good idea to get a separate commuting bike - if nothing else, it's nice to have 2 bikes for transportation in case something happens to 1.
2. A road-style bike. Heading into a wind on an straight bar bike is slower. If you're having trouble finding one with rack mounts, I know of at least 2 good racks designed to be mounted on a road bike without mounts.
3. A traditional derailler - in my experience, an IGH is slower for some reason and with a chain it's not actually less maintenance.

If you did really, really want an IGH, I would highly suggest you get one of the few models that uses a belt rather than a chain, as they look like they're *actually* less maintenance. I know the Civia Bryant is one of those those bikes. I believe Trek? makes a version with upright bars if you really wanted to go that way.

Let me put the time/distance tradeoff this way - on average a 20 mile trip might take 1.5 hours assuming you're in good shape, but might run into a few stoplights or something. If an IGH, upright handlebar bike is only 10% slower, that's 90 minutes * 10 times a week (twice each way) = 900 minutes, 10% of that is 90 minutes. So each week you'd spending 15 hours commuting, and an extra 90 minutes on the bike. Even with a belt IGH, it's very very difficult to believe that any extra maintenance you would theoretically be doing would be enough to make up for losing 90 minutes each week.

I want to be clear - I'm not someone who "doesn't like an IGH theoretically". I bought one. I own one. I rode one last summer, and still use it as my regular winter bike. And if your commute was 5 miles and you biked in the winter I wouldn't have a negative opinion about it. But having owned an used one, I wouldn't use it for a really long commute each day, based on experience with the one I own.