i have a 118g corner, has had water in it for 9 days.
the cons are limited space underneath for fuge (i had one custom made to fit the dimensions of the space to maximize room under there). also, limited space up top for lighting, but i got the coralife retro fit kit and was able to get it to fit. i had to keep it less than 24" long and 15" wide to still be able to open lid on canopy. but it has 1 150w HQI MH 2 65w actinics and 2 moon lights. the ballasts are external so they are not in the canopy. you can get one with a 250w MH as well, but i went with the 150w for now.
great place for corner tank is 4fishtank dot com comes predrilled and the finish on these are beautiful.
you will want to have a refugium. i fit a 30 gallon fuge, an aqua c 120 skimmer and a 1/4 horsepower chiller under there (which i probably wont need till summer) and i just added a phos-reactor filter off the side of the fuge.
i would have gone with a reg. shape tank but the only spot wife wouldnt freak out on me was in a corner in my computer room and a rectangle tank in a corner just didnt look right. and it does look really cool and its 30" deep so lots of room for corals. its almost 6 feet from one side to the other, so tang police wont mind a yellow tang in there either.
i'm at work right now so cant post pics, but look for thread started by cymbal67 photo diary of getting started and you can see it.