Not that you can go wrong with eithe one of those for sure.
The Z4 is very versitile, can go in just about any room, placed just about anywhere, and give just about any throw -vs- screen size you could possibly want.
I wish I could afford one. Even with a free replacement lamp, $2k purchases are near impossible for me. I'd use my current projector as a back up in case of failure if I could get one.
Pretty happy with my projector though in all honesty and it didn't cost very much at all.