I'm another one who likes voiced protagonists in games and I'm pleased to see more games taking this route. It feels more natural to me. Maybe it's because I don't see my character is "me", so they don't need to use my voice.
The only issues I have with this particular woman's voice in FO4 is that it sometimes sounds as if the voice actor wasn't given enough direction. She has hitches and pauses in some of her delivery, making for poor flow. Sometimes, it seems as if she didn't read the entire scene in order, so her delivery doesn't match the tone of whatever line came directly before hers. And some things she says just sound stilted ("I took care of those ghouls... (long pause) that were giving you problems...").
It also doesn't help that some lines are repeated over and over because of the radiant quests. That's an issue for both our protagonists and the quest-givers (looking at you, Preston).
Having several male and female voices from which to choose would have been nice, but I'm sure it would have been cost prohibitive, given the number of lines each has to produce. ((ETA: Choices would also be beneficial for second, third and more play-throughs, if people want to play a different personality (good vs mean and so forth).))
Anyway, in my opinion, voiced protagonist is a very welcome step in the right direction. Now it just needs to be polished up some..