What's the Downside for Current Root?

[Biofall]

I get my EVO from BB sometime next week (Rep said they heard rumors that previously thought 6-10 second-wave shipments might get in as early as monday for late pre-orderers like me) and I want to root as I used to be a WinMo ROM addict, but I keep seeing all this stuff pop up in threads about breaking 4G and marketplace. I live in Houston so 4G would work for me, and I want it. It's called the EVO 4G... Aaanyway, wanted to know what problems people are having with the root, and if the problems only come up if you flash a custom ROM, etc.. I'm perfectly happy with the stock ROM originally I'm sure, so if I just rooted, then did the recovery thing, what are the benefits/downsides? I'm sure that if I didn't root and accepted the OTA update another root will pop up, maybe even before I get my phone. And I don't want to flash custom ROM's yet because I don't want anything buggy with breaks like 4g, at least not when I first get it. So, respond please lol