I dun own both but I did consider before

jetta pro
- very powerful car even compare most of the car 150k and below
- FC is better than k5 (obviously the weight of jetta is lighter)

optima k5
- killer look
- D segment car
reason I drop K5 in list
- consider abit much of little problematic car (check k5 thread complain the noise, roof mirror and etc)
- lack of power (not that important)
don't get me wrong, I still like K5 very much.

I did, and never regret.  With black leather the car is so much classy now.
will do DRL as well, but got to wait for stock.