THe regular angle iron stand is pretty tough, I have notived that the "scroll" type metal stands can move around a little. It's really important that you have all 4 feet supported level so the tank has even support on all 4 corners. If one of the feet is high or low it can put the tank in a bit of a "twist" that can lead to failure or breakage. I use a 4' level on the stand and shim where needed. I also don't trust the stand itself to be level so onec I put the tank on the stand, I use the level again and shim the tank on the stand as needed.
I also have never had an iron stand fail. THey rust real bad over time though, espcially on saltwater tanks.
Joel