I have 3 250 watt SE on my 150 and 2 175 watt DE on my 75. I like both of them. The SE are nice that you don't need uv protection the DE are smaller. IMO a tough call unless you want to use a particular bulb that isn't made in the SE or DE version.
Hmmmm... so it just comes down to size and space occupied only! None of you noticed any difference in output, growth! I am planning to use reeflux 250W bulbs and debating for reflectors! DE has just parabolic reflector but SE has several choices like lumenarc mini/lumenbright!