Waaaaaaaaaaaaaaaaaa...............Nalu-cha­n your sooo meanT^T It's soooo hard to choose between themT^T

OVA 4 based on tenroujima story
OVA 5 based on GMG story...

but, I think OVA 5 has many ecchi than OVA 4

in OVA 5, a lot more scenes JERZA, whereas
in OVA 4, a lot more scenes NALU

Ova 5 was funnier and as azie_enbu mentioned there were many Jerza scenes I loved them :)

I like OVA 5 a little bit more because it's really funny :D
too bad there's no Nalu and just a bit Gruvia :( (well I think they've got screentime in OVA 4)

The Jerza moment was just awesome

heh ova 5
there's fun