It is very hard to know which is best, maybe you could sign up for the 'Which' magazine trial and have a look at their results.
I bake a lot and put in a new oven couple of years ago, I went for mid range price and got a Bosch, it has a slightly wider oven cavity than most ovens which can be very handy. If I had the room and could afford it I would put in 2 single ovens rather than a double as I have found the second oven on a double not much use really. I now only have a single oven but I actually mainly use it for baking, at the moment the chicken roasting for lunch is in a halogen oven in the utility room.
For baking I think it is important that the oven has a static function as well as the fan, most do to be fair but the odd one does not. My previous oven was a whirlpool, useless piece of rubbish for baking but fine oven if you wanted to roast something. Wouldn't mind but I bought the top of the range at the time, many years ago now, was newly launched multifunction oven that was practically going to bake the cakes itself, it was awful, fan was so strong that as soon as the buns rose to top of tin it basically blew the mixture over the edge.