Hi! First time too and my EDD is also during xmas week! Please let me know who to PM about the WA group, it seems like damahome is busy heh.
We have chosen Dr. John Tee at KKH and we have decided on Harmony test (have not gone for it yet), despite being in the low-risk group.
Also OSCAR test is not know for being highly accurate (as compared to Harmony), so if you are the sort who really need a lot of assurance, if OSCAR test is negative you may still need to go for Harmony so that's like a double cost... Plus point about Harmony is you can get to know the gender earlier hehe.