Jump to IVF? Or is it too soon?

We've been trying over a year. We are on cycle #16. We have done all of the normal testing, and we're fine.  All of the numbers are great on paper but we're not getting pregnant and we're only 25, and thus we fall into the terrifying "unexplained fertility" category. We did one IUI with no drugs, which failed. Now we are doing an IUI with injectables. I was talking to my RE today and she suggested jumping to IVF if this IUI fails. She says that with unexplained fertility, more IUIs might end up being a waste of time and money based on whatever our problem is (which of course we don't know). But IVF would probably work and it's where we'd eventually be headed anyways. What do you ladies, who have been down this road think? If insurance will cover most of it (supposedly we will hit out deductible and it should) should we do it? Do IVF in December? Is it too soon after only two IUIs?