Well, well!! You learn something new every day or so. I hadn't noticed that Revell had released a 747-8I, I thought they only did the -8F. So that's why I said that there was only the -8I from Zvezda which was released a few months before the Revell -8F.
Anyhow, I don't feel inclined to spend money on a nice Revell kit so I'm stuck with the Russian one. Here's pictures of what you get in the Revell and Zvezda kits. As you can see, there is less in the Russian kit and the moulding is not as crisp. The decal sheet is for a prototype, which doesn't suit me and whereas the Revell kit gives you a virtual tome for the instruction sheet Zvezda gives you an A3 size sheet printed on both sides. Still, I hope it ends up looking a bit like the real thing.
Here's the Revell -8F kit
And here's the Zvezda -*I kit
I'll keep you posted on how it goes.