Is the choice at the same airline?
If so, I would go with along with what provides you with the routes / lifestyle / personal preference. Why? because if the airline gets rid of one type they will convert you in the future.
Is the choice at 2 different airlines?
Think longer and harder. Which airline is more likely to be around in 5-10 years? Which type rating is at the airline you believe to have a longer future? Probably go for that one, for the reasons above. If you think neither will be around, then go for the rating better saleable to your next employer.
imho .....