As long as you read before hand...and do research...no real danger at all...Do it...it is awesome!!!!!!!!
Ooooo such bad info in that answer...
there is a very real danger in rooting..and yes rooting does void your warranty. If the rooting process goes bad, you have an expensive paper weight.
if it all goes right. you have to make sure to only use ROMs made for the CDMA Hero. using any other ROMs will brick the phone.
OK, the danger part has been laid out.. now the good stuff. Everyone is getting all worked up over not having 2.1 yet... there have been 1.6, 2.0 and 2.1 ROMs available for months. Recently the 2.1 ROMs have been based off a leaked Sprint RUU. 2.1 is awesome and everyone that isn't rooted has to wait until Sprint gives it to them.
Also, being rooted means that Sprint doesn't control what apps you are forced to have. I never used Sprint TV, NASCAR (I like NASCAR but the app wasn't worth it) and NFL (I don't like football so sue me).. Peep sucks compared to other apps.. footprints.. I could care less about footprints..all of those are gone from my phone.
Now, should you root or not? that's a personal question. But if you are the kind of person that loves complete control over things, or loves to tweak and customize, then root. if you understand the risks involved and are fairly computer literate and don't go into full blown panic mode as soon as something doesn't work exactly like you thought.. then root..
if however you freak out if one little thing fails.. or panic over an error message.. or don't understand how to uninstall and reinstall applications or drivers on your computer..or even have basic command line experience... then you might not want to root.
If you do root, and IF something doesn't work exactly right, there are plenty of people on here with the knowledge to get you past any bump in the road.
Come to think of it... that should be one of the best reasons to root... some of the nicest, most helpful people can be found in this forum..