Why would an end be so unlikely? I think it's more a 50/50 kind of thing actually.

As Stephen Hawking proved the universe pretty much most certainly had a start (his reversed blackhole theory) and has been expanding ever since the Big Bang.

I think infiniteness here is a somewhat semantical thing. Does 'ever expanding' mean 'infinite' also? Or does it have to be 'without boundaries'? What if it has a boundary that's expanding too fast to ever catch up with? I'd say that would qualify as 'infinite' from our perspective as well.

I'm guessing the bottom-line of the question itself whether it's finite or infinite has got more to do with the potential of being a reoccurring event on the largest scale.

I have no idea what Hawking and co. think of that though.