Hello!
I recently updated from Unity 4.0.something. to 4.3.
After I copy pasted my entire project folder into the new software’s project folder everything imported good. [for the most part]
The main issue is the terrain texture, which seems to be in extremely low resulution 
I tried lowering, increasing it’s resolution from the terrain settings, [i did not mess with heightmap at all], but no change.
If i add a new texture to my terrain, it’s the same problem. Low texture
Look:
http://imagizer.imageshack.us/v2/800x600q90/812/im7r.jpg