Hiroo
If I were you I would buy them both;) !!
They are both very impressive visually, and encompass the size, scale and scope of the two campaigns very well indeed.
I've only played against the AI in an F40 campaign so could'nt comment on the German's prospects HTH; but like them all I supose it depends on the quality of play generated by your opponent.
Irrespective of the Campaign balance there are some superb mid sized scenarios to be had aswell - as has already been commented on the MB the "Gembleux Gap - Battle of Hannaut" and "Breakthrough at Sedan" are excellent
S'42 again is excellent - massive game - really good feel of the expanse of the steppe, and the desparate choices that the German faced, coupled with the requirement that the Ruskis have to plan carfully due to slowness of the infantry advance vrs distances to be covered
Not much help this I suppose - so like I say - get them both !!
Cheers
Chris