plywood or glass?

I am planning on redoing my system this summer I am going to tear down my 300 and move my fish room to another room in the basement and put 2 240 gal tanks side by side built into the wall one will be a mixed reef with only small reef safe fish the other will be a softie only reef with fish that are agressive and maybe not totally reef safe (angels, large wrasses, triggers, eels, lion fish and mabe a puffer). 
I am thinking of either building them myself out of plywood or buying them from glass cages these are my only 2 options that I will be able to afford.
the tanks will be 48x42x29 with an external overflow if built out of plywood or 48x48x25 with an internal overflow if i buy them from glass cages. both styles will have starfire front glass and a closed loop system powered by a reflo hammerhead with a ocions moitions. 
if i build it out of plywood total cost would be between $1800-$2000 for both if I have glass cages build them it would cost about $3600 for both.
I have heard mixed reviews about glass cages tanks but I have seen a couple of them that look good plus I can use my mp40 along with the closed loop 
I have also heard of plywood tanks lasting over 20 years if done correctly and they would cost half as much but they are alot of work to build, and i can only do a closed lood system for water movement and face its wood so if its not done correctly it wont last.
so basically what do you guys think plywood or glass?
 
anyone with first hand experince with glass cages aquariums or plywood aquariums please chime in

 

I didn't design the stand I just built it but the plywood design is pretty much straight forward