Projectors: Lumens or Contrast ?

I am planning to have a display set up for the outside view using one projector.

i am considering either the Optoma GT1080 or the HD25-LV.

One has higher contrast (25000 vs 20000) but lower lumens (2800 v 3800).

Question is: for the intended usage, which is more important, lumens or contrast. (throw and price put aside)

thanks

It's a balance really. And I think it depends on the level of lighting you plan to have. High lumens help a lot if you have some light in the room and want to still see a bright image, like in conference rooms. If you plan to have a fully dark room then more weight goes on contrast ratio. I have the HD25-LV. It's excellent. I don't always have fully dark settings.

cheers
Rob