I have enjoyed the games of 1900 that I have played. I think that the variant is very good at balancing the game. But I also believe that there is limited opening strategy for Italy and Austria (and the other countries but not as much). Tactics don't seem to play as much of a role in the game.
I think that opening moves in 1900 heavily rely on diplomacy. For example, the Switzerland problem. There aren't really any effective auto-pilot openings.
Well so actually, I think this is a bad thing, and the reason why I think regular diplomacy still wins. In 1900, the emphasis is really on how countries communicate with eachother, and not on the tactical aspect. Of course, it's still there, but I spend very little time thinking about my moves in 1900 whereas in regular diplomacy I can spend a very long time analyzing any particular position. There are volumes on all the possible openings for each country, but very little for 1900. Yes, 1900 is less popular, but I'd argue that from a tactical aspect it's also much less interesting.
Though I may be biased because I actually love the fact that trieste and venice border eachother. I think that it is what makes playing Italy and Austria so rewarding and interesting in the regular game. Without the shared border, they are not nearly as fascinating or interesting to play.
Anyway, what do you think? What is the better game and why?