If you read through this thread you would know that this is a very "do it at your own risk" process. You would also have seen that many of us said these things early on. However, the link I provided actually does have one of the guys at xda explaining how to back out of this.
As for the link you provided, the post stated that if you use the RUU you can't root the phone.
This is totally false. In fact the RUU is rooted itself, but you must use adb to take advantage of it. If you want the normal root you are used to, then you must root your phone, as I have done, using the normal method. Rooting works perfectly fine.
The link you provided also stated that you can't go back once you RUU. However, the link I provided had someone telling you exactly how to do this. I have not personally tried this because the RUU is working so well on my phone there is no reason to go back now. With a little work I got the protected apps running, installed busybox and got my phone how I wanted it. I'll probably stick with this until after the final version comes out and root is confirmed.
The reason I need root is because even though the 2.1 build from sprint is fast, it gets even faster once you remove all the extra apps you don't use. Also, I imagine eventually the devs will figure out how to get live wallpapers and other 2.1 goodies. So while this RUU is not the be all end all of ROMs, IMO it is right now the best one for me. My only problem with your previous post was that the information was totally false.