I personally hate all gas fires regardless of flue type. They are often ugly, I prefer electric fires as they look good and are not massively expensive to run.
But then I am in the camp of "only want to service combi's" too.
You need to supply more info like what area you live (obviously cost changes around the country). And you should ask what a basic service is? I have never of different levels of service but maybe they are trying to sell you some useless extras. Also the cost can/will go up depending on how many gas ...
