The metallized is probably better film if the price difference isn't too great.
Tint is somewhat personal preference and somewhat local laws.
Having had various tints:
20 all around would probably be my choice if the law permitted it.
35/20 is a good practical tint - good front visibility outward and good rear concealment. You have to decide if it bothers you if the rear windows are darker than the front.
35 sides and 20 rear would be less noticable that the tints don't match.
35 all around is all my state allows and therefore what I would go with - however - you will be able to see inside the car clearly (especially on overcast days or at twilight).