I don't think any two game animals of even the same species can be compared fairly. There's too many variables on how they were cared for in the field, state of animal when killed(running), processing, animal condition, etc.
That being said, I love moose and have had excellent Caribou. I think the worst meat I've ever tried though was rutting Caribou. Seriously, if you're hunting the Caribou rut, donate the meat. Caribou bulls have been known to die from premature liver failure, due to injesting cow urine.
I'd bring home more Moose than Caribou if it were me.