Normally everyone is taking the TV-Internet-Landline combo deal which makes a lot of sense. As for the speed i would say 40-60.. 40% of the time you would get the actual speed and 60% of the time less...

But its getting better so just be patient and am sure you will get used to the things in Doha.

I would suggest to stay away from Vodafone as they are having lots of issue in terms of connectivity and pricing. Go for Ooredoo which is more stable and the connections for GSM / 3G are much better. Plus they wont cheat you like Vodafone normally does.

I wish you good luck and welcome to Qatar.