Pretty surprised there hasn't been a thread about this yet. On Christmas Day, a fan translated patch of Valkryia Chronicles 3 was released. You can check it out at http://vc3translationproject.wordpress.com/
Currently the patch isn't 100% perfect. The translated patch covers the main plot threads, character names, menus, items and basically everything you need to play the game from start to finish. If you haven't done so already, I strongly recommend playing VC2 before going into VC3 so that you're comfortable with the mechanics.
In addition, you can do this all legally if you purchase the game from the Japanese PSN, then use PSP CFW to export the ISO. The game is on sale right now until Jan 8th for ¥980 (or roughly $9.32). If you need more info there are directions on the site on how to do this. AFAIK, you can only play the patched game on a PSP or PSP emulator, I don't think it's possible to play on a Vita.
So my initial impressions are overwhelmingly positive.
The game starts off much better than VC2. The game throws you right in the thick of things rather than training at a military school. The protagonist is leagues better than the one in VC2 who had this creepy obsession with his brother.
There are also several visual improvements over VC2. The character models are diverse. There isn't simply a male and female model with different heads strapped in this time. Characters wield different looking equipment and clothing even if two characters are the same class and gender. Cutscenes and battles take place on an war map. It's much easier to see how one cutscene leads to another rather than shifting through menus with dates on them. The game just feels more cohesive and well put together than its' predecessor. It's a shame that Sega didn't bring this overseas.
The only downside I've encountered so far are the maps. I played roughly 4 hours now and 75% of the maps are identical to the ones featured in VC2. The camp and bunker locations, construction points and the grass/shrubs are completely point for point identical to the maps in VC2. I know "lore-wise" it makes sense since the game does take place in the same setting as VC2, but it seems like a cheap copout by SEGA.
Overall though, I still highly recommend getting this game if you looking for something to play during the winter break.