I have mustache bars on my Bike Friday NWT, which I used for rides in the country while I was on vacation in France this summer. They are set up with road levers on the forward bends, bars slightly below the saddle with the ends pointed slightly up. My primary hand position was on the outside of the bends, just past the brake hoods. I also used the far ends and the hoods themselves. This was my first real use of 'stache bars. I found the bars to be pretty comfortable (I had already taken some time at home to get their position set up) but for longer rides I would prefer drops in the future. For city riding and shorter rides, however, I think they would work perfectly well for me. I might could have been more comfortable if the bars were slightly above saddle height (I couldn't get them that high), but as they were they were good but never quite right.
On the other hand, I suspect they will work very well on my girlfriend's bike - I have it currently set up with drops and interruptor levers, and she spends nearly all her time on the tops (largely out of habit, I think.) For someone like her, I think mustache bars will give her more hand positions that she is more comfortable riding in with easy access to the levers.
You mention that you could not get the bar high enough. Was it higher or lower than the tops of your regular roadbike?
And compared to your regular bike, did you use a different (shorter/longer) stem?
I can't say exactly without unpacking the bike and looking at it again (it's been in the suitcase since I got back), but I recall the stem clamp being at about the same height wrt the saddle as on my various road bikes, though those are not all the same - they are at about 3cm below on two of them and another incc or so lower on the third, despite which I probably find that one the most comfortable. I have heard that mustaches are best slightly above seat level, and my experience so far tends to support that for me. My NWT had the bars as high as I could get them. I used a much shorter stem than usual - my goal was for reach at the hoods to be about the same as on the ramps on my Noodles.
I have Albatross bars on my One Way and I love them.
I test rode a bike with mustache handlebars when I was shopping for a new Rivendell bike. For sitting upright, I did not like them because the brakes were not right by my hands. I would be in trouble if I had to brake suddenly, which happens all the time when I commute. I ended up getting albatross handlebars, which are great for sitting upright.
I have wide mustache bars with time trial brakes on the bar ends. The ends of the bars are pointed slightly downward, similar to drop bars. Hands near the bar ends is my normal position; I sit very upright, which I like for stop-and-go city riding. The bends I use for stretching out when I'm not in heavy traffic; it's still a fairly upright position with good visibility.
I prefer shallow drop bars for touring (more hand positions, and the possibility to get lower in a headwind), but for the city, mustache is at least as good, maybe better, since I never use the drops in the city anyway.