"bricking" your iphone doesnt happen anymore. the biggest issue i ever encountered installing the beta was having to put my phone into recovery mode and having to start over again. if i remember correctly, apple is no longer legally allowed to turn your phone into a $600 paperweight because you try to jailbreak/install software other than what they provide you.
anyone feel free to correct me, but i believe your worst case scenario is install it incorrectly, be asked to register your udid, put your phone into recovery mode (hold home + lock till it restarts, keep holding, plug your phone into your computer, wait until recovery mode screen pops up) and either restore back to ios6 and give up, or go back and retry installing ios7