OK, an idiot's response (I have no formal education in things biological):
IVF is just turning a viable zygote into a human.
Cloning you have to produce identical viable zygotes first, and that after identifying what zygote you prefer someway or another.
Okay, idiot's retort:
I thought IVF started with getting some sperm to fertilize some eggs. I assume this isn't easy and required a lot of trial and error to get to whatever success rate we enjoy today, which I also assume is not 100%. Then I think they choose something like the 5 or 10 most viable to attempt to implant. I would think this part would be pretty much the same as with clones.
With cloning, I assume the difficulty comes with trying to combine the DNA with an ovum. I don't consider failures here to be any less ethical than abortion, and certainly no less ethical than IVF failures.
Now, the question is, are there higher rates of failure further into development, and if so, why?