You do hear a lot of reliability problems (actually it's usually about the pawls slipping which seems to be a result of cable slippage or dirt in that part of the system) but I've not had much problems with mine. Since everything is in one unit rather than distributed as in a derailleur system it's easy just to say "it's the hub" rather than one of the subsystems within the hub.
Having the 1:1 ratio where it is is probably due to how they (Shimano) developed it, to get the 11 gears there's a funny double shift between 6 & 7 - you can feel a different "clunk" when you change gear - I think it's due to there being a second planetary gear for the extra (upper) gears.
I found the gap between gears to be too big with the recommended 1:9 ratio but swapped out for a larger sprocket and it's fine, even though I'd spin out on downhills but then I'd prefer to coast at those speeds. I don't use mine off-road, it's on the commuter where high speed isn't what I'm after. A couple of years in and about 4K Km and I'm happy with it. Not sure if I'd get another one but it's likely to last me a good few years yet.