Hmmm, I have only ever owned two FWD cars. I have otherwise driven RWD and AWD cars. My RWD BMW works fine and I have never had a problem. I guess you will have problems if you drive too hard in a RWD car in bad conditions.
When I used to drive in the USA in snow storms I observed the following. If you drive too fast you will have the following reactions in icy and snowy dangerous conditions.
FWD: means when you crash you slide into things headfirst.
RWD: means when you crash you can slide into things backwards.
AWD: means when you crash you spin off the road. Very graceful pirouette!
I have seen so many people forgetting no matter what kind of car you drive they all stop obeying the same laws of physics.
Being a fairly aggressive driver I can tell you that I don't like FWD vehicles in snow and ice as when you start to loose control you tend to understeer and you don't get control back. I prefer RWD over FWD because you get the front wheels steering and the rear wheels driving. This means that all of the work isn't being done by just the front tires.
AWD is very nice if you exercise some basic caution. If you drive too fast nothing stops you. You can't break the laws of physics just because you have AWD. Also, if you feel yourself start to slip you can gently power out of the situation. One down side of AWD is that there is extra moving mass in the driveline. This can make a difference in how the car handles. This gives the car more momentum which can be a good thing or a bad thing.
The different types brake differently as well. For example with AWD if you lock up one wheel and all of the axles are connected and you could end up rapidly locking up all of the wheels. With FWD, you are likely to effectively lock up the front wheels if you decelerate too rapidly. With RWD, you can lock up the rear wheels if you decelerate too quickly in slick conditions. This is why some people like FWD as it is the most forgiving in these situations. This is also why I wouldn't recommend buying a modern car without ABS. (Don't know if you can.)
The real reason I like AWD best in this country is that it allows you to accelerate in a straight line no matter what the road conditions are. Unless of course you can't move at all. My wife's A4 with FWD was scary in the mountains as on hills it would slide sideways when I was trying to go uphill. RWD does it less and AWD hardly does it at all.
If you have FWD you will need chains, unless you don't care about getting where you are going. They put the chains required signs in about the right places every time. I found that even good snow tires don't do well enough in the steeper parts of the mountains. And in this country it doesn't take much until you are there.
Yes, AWD cars will get slightly less mileage. From .5 to 1 L/100km depending on how the AWD setup is designed.
Good Luck choosing,
Brian.