Yes, you will have to root, please refer for this at LG Eve GW620 Rogers rooting guide + Remove Rogers apps
And this is a unofficial release and a beta one. It works well but some things are not working perfectly, like the camera is limited to 3 MP for now, video mode does not work, the FM radio does not work yet but most of the stuff works well with a few bugs. Since this is beta software, don't expect everything to work always.
My opinion is that the developpers have made a wonderful job and for me, 2.2.1 with a few bugs is definetely better than the 1.5 firmware provided by LG. It is more responsive and it is quite stable.
I suggest that you take the time to read the documentation on OpenEtna website before deciding if you want to try the update. Or, if you prefer, you wait for long months before LG issues out an hypothetical 1.6 or a "too beautiful to be true that we'll probably never see the light" official 2.2.