Of the two mentioned I would recommend the 10s for all around use. The 12s will excell when longrange viewing is needed. But in the woods they will be a lil tough to find stuff quickly with. If you aren't the steady type you will likewise find yourself giving your eyes a fit with shakiness. I personally prefer and use two types, a 15x for field/longrange use and a 9x for woods and closer range use.

Like I always say, the Monarch series binoc is THE best optic on the market for the money. QUALITY stuff!
RA