I have heard that the newer ones are just as good as the older ones, but I have no first-hand experience with that.
Currently I have a 1954 94 and a 1980 model (XTR variant). Both in top shape. The 1980 model is every bit the gun the pre-64 is, and has a smoother operation than the average pre-64 I've handled (maybe a dozen total). Unless the gun is for collecting and not carrying/shooting, I'd easily recommend a post-64 on my experiences.
As to caliber, my decision was that if I was going to tote a rifle around, I was going to tote it with a rifle caliber and not compromise it's performance with a pistol caliber. The proliferation of pistol caliber guns is more to suit the competition use of the gun in re-enacting where high-volume, low price, and short distances are more important than absolute ballistic performance.
The re-issues coming for the 94 in 2010 I read about where both limited edition commemorative pieces (e.g., bling and $$ and not field guns). Barely used ones are plentiful and cheap. I have examined but not fired the new Mossberg copy (I think the "464"), but reviews have been uniformly positive. So if you want new/warranty/ease of shopping, you could grab one of those.
What is the advantage of the M1A or Steyr Scout over a Winchester model 92 or 94?
Cartridge performance (.308 vs. .30-30) and volume-of-fire, and at the expense of weight and ease-of-carry.
I considered the scout/squad very hard and almost bought one, but the bulk, weight, and fact the .30-30 did all I needed at considerably less price and a much more "packable" size weight made me move off of it. The .308 is more capable than the .30-30, but not "order of magnitude" better. The volume-of-fire aspect is more suited to squad tactics and not that immediately useful for a civilian shooter.