The Monster 3D II is a bit late, but certainly not too late. The benchmark results show that there was nothing wrong with Diamond's initial decision to go for only an 8 MB solution. The option of getting a 12 MB version as well is pleasing though, so we can thank Creative Labs for kicking Diamond's butt a bit, forcing them to this change of opinion. If you don't know if you want to buy the Creative Labs card or the Monster 3D II, these points may help you making a decision:
Currently it's almost impossible getting a 3D Blaster Voodoo2, maybe the Monster 3D II will be easier to get.
If you care about free games, this may be something that appeals to you. Creative doesn't bundle their 12 MB Voodoo2 board with any free software.
If you are into that, but don't like playing around with the Windows Registry, the Monster makes it easy for you to change the clock speed. However I would have preferred a slider that goes up to 100 MHz.
Overclocking, The 2nd
If you want to run your Voodoo2 board at speeds of 100 MHz or more, you may not like the fact that the 3D Blaster Voodoo2 is not very stable at all at this speed. The Monster 3D II is definitely the more stable 'overclocking solution'.
Be crazy, only go for the best and biggest
People like me always want to have the best possible hardware solution in their system. I don't care about registry settings, neither about free software . I want as much memory as possible, although I know best that it hardly makes any difference.
I guess that Creative Lab's card will be cheaper in the long run. Creative has got a lot more ressources to play with than Diamond if it comes to some kind of price war.
Diamond has got a big name in the graphics business, while Creative Labs are famous for their sound cards. It's difficult estimating the support from Creative Labs, whilst the graphics support team at diamond is pretty experienced. Diamond is also famous for their Monster 3D board, which was the most successful Voodoo board, so that may be kind of important to you.
OK, hope you could come to some kind of decision. Maybe you can wait for other vendors like e.g. Canopus, Quantum3D, Miro, Guillemot, ... or you want to wait until Diamond comes out with their 12 MB version or Creative with their 8 MB solution.