I flashed SFR on an Epic 4G for the first time just the other day, and bricked the phone (couldn't get past the boot screen, and couldn't get into recovery.)
I can vouch for successfully restoring the phone using Odin in the link Paul627g referred you to above, though I used the EC05 restore (procedure #1 in that thread.) I also initially rooted the phone using the method Paul627g refers you to above, as well--follow the instructions, it truly is a simple, 1-click procedure.
I think it's doubtful you will experience any trouble, as long as you follow instructions exactly as written (I'm not a programmer or a techie, but I've had no trouble rooting and flashing many phones, dozens of times at this point, using resources from this forum and XDA. Still don't know what happened the other day, but that was the first time a flash didn't work for me, out of probably 50 times by now.)
And if you do run into trouble, the restore process isn't difficult--again, be careful to follow instructions. It only took me a few minutes to get it straightened out. I'd recommend having all the files downloaded before you start so you can get back up to speed ASAP in the unlikely event you do hit a snag. But as long as you can connect the phone to your PC and get it to turn on, I'd guess that it's damn near impossible to literally brick this phone.
Just be careful, take your time, and pay attention to detail--you should be fine.