I'd say this is a common question thrown at me since I got to Doha a couple of months back. I don't think there is a definitive answer to it. Both cities has its own beauties and scars. No city is perfect, and to expect a perfect city is paving way for disappointment.
If you ask me what is good in Doha, I'd say there are a few aspects. The prime thing that comes to my mind now is the traffic flow. There are single lane roads here too, but at the junction of such roads is a roundabout. This ensures that people don't squeeze in their vehicles in any little place available, and cause traffic jams. Following the rules of roundabouts surely creates a smooth traffic flow. Another thing that I've noticed is the absence of urine stained walls. (You know what I'm talking about if you are from India. I don't know about other places though.) Roads are pretty much clean too. The desert sand is abundant on all roads, but not much of garbage lying around (may be I'll find that things are different if I visit the older parts of the city).
But what is the use of clean and neat areas when you hardly walk in this city. The only walk I do is getting to different rooms in the house, and from the house to the car and back. If you ask me what I miss the most about Bangalore, I'd probably say it is the walking. Walking for more than 2kms to reach college during my PU times seem priceless now. I miss the (crazy) auto rides. I miss seeing traffic jams because of the haphazard driving. Why do I miss that? Because once the offending vehicle moves out, it is a pleasure to see the way jams clear out.
All said and done, each city has its positives and negatives. The earlier you acquaint yourself to this truth, the happier you will be in the new place as well. Enjoy each city for what it offers and am sure you wont be disappointed.