I'm not rocket, but I'll answer your question anyway
. Having had a brace on my manufactured 75G stand and upgrading to no brace on my new DIY 220G stand, I can say that no brace is much better for access under the tank. On the 75G tank I was unable to remove the sump without removing the tank, and when I wanted to upgrade the sump after the tank had been set up for a while I discovered that it was impossible. Even if you never have to change out your sump, just having unhindered access to the bottom of the tank makes life much easier. For my 220G stand I designed a removable frame with four doors. For day to day access I simply use the doors, but if I need to do a lot of work under the stand I can pull off the whole frame and get access to everything with no brace or anything in the way.
Now, that said, if you're planning a separate fish room or something and won't have a sump under the tank, then you can ignore all of the above. If the stand will just be for storage then I don't think a brace would be a problem at all... But if you are planning on putting a sump under there, skip the brace.