Theres no wow, yet. I was going to wait until a full sense rom, but it just gives you more control over your phone. Like someone else was saying, custom notification bars and graphics, custom boot images (though this may be possible stock now), removing/disabling apps not used like corp mail etc that auto-launch themselves, and even when you install the apks made for unrooted phones it still leaves you with 2 versions of gallery or clock etc, but with root you can make it the only (and backup the old) etc.
It just gives you More of everything, and when the good rom Finally does come out, you will be able to load it up in minutes.
Also there is no disadvantage to doing it, and most people that can both read and type can do it without a hitch. There is nothing technical involved at all. You open your command prompt and type exactly what they say. You don't even have to know what mount is.
And once you've done the image recovery step, nothing you do from then on (software wise, not dropping it) to your phone can ruin it, you can always restore to a working version. So relax, and try it if you want. It won't cost you anything but 15 minutes, and if you ever want to return it and are paranoid, maybe 10 minutes putting it back to original.