Hi Harry,
You have the Fischer set? What would you say are the high and low points? Can you make any comparisons with other versions?
It costs less than 100 euros for ALL the symphonies, and I almost bought it.
I am happy with my sets of Paris and London symphonies, so I am really looking for the best versions of the middle-period symphs,
say mid-20's up to 81.
I have the full Dorati set, but on LP. A comparison between Fischer and Dorati would be great.
It's my birthday soon, so I need to start lobbying soon ...... 
Lets say from Symphony No. 1-88, there is no problem at all, the best performances you could wish, both in sound and in interpretation!
My principal concern is with 89-103, but the problem is not that big, that I would not buy it again.
Not sound, because that is good! But those were recorded first, and Fischer was clearly searching the right mould. You can hear that mostly in the menuets, very stiff upper collar, as with all the menuets from Dorati. And he tends to take the Allegro's and Presto to slow, not always mind, but he does. Furthermore, he just wants to be grand in the name symphonies, and that tends to sound somewhat overblown.
So reading your wishes, Fischer would do just fine.
That said the Fischer set is a must for all Haydn admirers, and I would not like to be without it.
Have the Dorati set too, and that is also a must for me!