This has been something especially the MS side has been talking about because the ODF 1.0 specification doesn't really contain much in that regard. I find it quite lame of MS since they had every chance of taking part of this process when ODF 1.0 was created. When MS says that ODF don't support what they need, then it is really their own fault entirely. Of course, there is no doubt the reason is that MS wants to keep their monopoly in the office marked.
Back to the formulars which is an area where MS says OOXML is vastly better than ODF - this wikipedia entry shows that history is a bit different and that in fact no such specification have existed until now. The formular support for ODF is now well underway and it will end up in an upcomming version of ODF. Rob Weir, an ODF support, has posted an interesting analysis of how well OOXML actually does and his conclusion is a bit scary:
As I've shown, in the rush to write a 6,000 page standard in less than a year, Ecma dropped the ball. OOXML's spreadsheet formula is worse than missing. It has incorrect formulas that, if implemented according to this standard, would raise important health, safety and environmental concerns, aside from the obvious financial risks of a spreadsheet that calculates incorrect results. This standard is seriously messed up. Shame on all those who praised and continue to praise the OOXML formula specification without actually reading it.Here is another post that follows up on Rob Weir's post and the conclusion is similar:
So when it comes to comparing MSOOXML and ODF v1.0 on the basis of the inclusion of "Formula Definitions", it becomes clear that the anti-ODF folk have not much to shout about. In fact MSOOXML's "Formula Definition" is deficient and inaccurate. As Rob Weir pointed out, in addition to this CEILING problem, most of the other formulae are inadequately defined and not well tested.I recommend reading both in full. I haven't spent time checking these by reading the specifications, so I can't say for sure that these posts are correct but I haven't seen anyone refuting them either.