Thinking of going 150w HQI to 175w SE. Advise!

[OCDP]

This is a crap shoot.... but I have a good deal on a 175w PFO system.

Just seeing what others think... if I should, or shouldn't.

Right now I run a 150w HQI over my 20g tank. I have been offered a 175w SE system. What would be better? I am not worried about the extra 15w of lighting for heat or anything...

But would 150w HQI be the same intensity as 175w SE?

Basically I just want to know if this would be a waste of time (no noticeable difference in corals,etc...) Or if I should take it into consideration. The price is right... just to note.

Thanks guys.