I test drove both the Taos and the Tiguan before purchasing the Taos SEL 4Motion about a month ago.
If I had the need for a third row or towing capacity, the Tiguan is the better choice, but the drive feel is different and the fuel economy is significantly worse. Driving in congested city streets, I was seeing gas mileage in the low teens for consistent stretches in the Tiguan, while the Taos seemed to say in the high teens to mid 20s even while moderately accelerating. You can also feel the size advantage of the Taos more when trying to find and locate parking. On the highway at cruising speeds the differences in driving experience are fairly small. The Tiguan might be slightly better at passing due to the increased horsepower, but the advantage isn't so huge that it'll keep you up at night. The turbo on the Taos kicks in at pretty low RPM so you the torque is there when you want it.
The only changes I'm looking at making to my taos at this point are getting some quieter tires. The factory tires perform well, but they are fairly noisy on concrete highways. It doesn't completely ruin the ride, but you feel the need to turn the stereo up.