Cycling in Sydney Australia
I’ve had a couple of bikes with derailleurs which I’ve used for commuting and all worked well if you kept them clean and adjusted (which I never did).
Allowing dirt to collect can cause the chain to jump or even come off. In a worst case scenario (yes this happened to me) the chain can jam in one of the stays and break, which pretty much puts an end to your ride. (not too many of us carry a chain breaker or a spare master link on a commute).
After that incident I bought myself a bike with an internal 8 speed hub, the Shimano Nexus, and I’ve never regretted it.
Apart from adjusting the chain tension every now and again the gears have been maintenance free for about 4 years.
Here’s some pros and cons;
Heres a pic of the one I've got on my 5 year old bike.
Pro: you can use a heavier (stronger) chain to make your bike even more reliable.
Pro: your trousers don't get caught as easily with a non-derailleur setup. Why, I don't now - they just don't.
Pro: nearly silent running.
Pro: you can run a belt drive and still have gears (if that's what floats your boat)
Con: hub gears can and (very occasionally) should be serviced - this requires a wheel re-build, making for a pretty expensive service every now and then.
I bought a bike with Shimano Alfine 8-speed about 3 years ago and I've not looked back. Actually, I can't imagine buying a bike with a 'standard' derailleur. All you people buying bikes with derailleurs are nuts!!
Phil - i reckon you've got about 500% ratio with your 27 speeds. Hub gears struggle to match that overall ratio - but they can come close; the Rohloff 14 and Shimano Alfine-11 are pretty-much there.
Saving $400 a year - given the life of these things you'd be up for some serious savings.