The Gladius is a better spirit weapon than the Bastard Sword, imo. The Gladius has two less average damage while boasting 25 more critical at all/40.
As a justified conclusion requires a detailed comparison of the exact numbers, it's necessary to actually know the stats for these ego weapons at all 50. Below are some ego stats at all 50 not known to some NA players yet.
First of all, ever since the cap has been lifted to level 50 several months ago, stats at all level 40 is just as meaningless as stats at all level 25. The point is that lv40 stats are no longer end game by any means, and instead just one point in your progress to the end.
Second of all, when choosing the best spirit weapon there are two most important things to consider: Damage and Critical. Now, the bastard sword ego takes the cake with its highest damage at all 50 (the most useful with windmill since critical with dual wield matters little after 30+):
[Image: http://img821.imageshack.us/img821/43/262855042860c7dc67b15cf.jpg]
The Muramasa takes the cake for its highest critical and the second highest damage as shown above in my earlier post.
What about the gladius? It has neither the best damage nor the best critical at all 50. Refer to below:
[Image: http://img94.imageshack.us/img94/1108/2667124fe06a91b6bfee99.jpg]
The only redeeming feature for the gladius is the fact that it has an impressive min of 100+ end game. Though this only appears impressive since max is much more important than min.