Well, since version 1.2 HDMadness has officially removed the "flasher required" warning and thus far there haven't been any brick reports... of course there is always a risk (even installing Sony's OFW updates) of bricking, but ErmaC CFW is basically the same safety wise as the others now.
I'd check out THIS guide as it covers making a NOR/NAND dump using multiMAN or memdump before installing any CFW to have a recovery backup in case of any bricks. Also another worth a peek is Itskamel's n00b Guide (scroll down). Always better to be safe than sorry
It's more stable and less buggy than rogero, that i can tell you. Rebug 4.21, that's the better new cfw all around, it offers a lot (perhaps too many for the common user?) of options and perhaps the most stable of them all. For game compatibility this ErmaC and Rogero might be equal on performance and the best options since no patches are necessary to play the latest games.