If you don't mind the heat, go for EK. However, recall you won't see an A380 Captain upgrade for 10-12 years. You may upgrade faster at the other growing UAE airline. If you can't stand extreme heat for a few months per year, go for TK. Both are fast-growing airlines with expanding hubs. I would have your spouse weigh in heavily on his/her preference as well since you will be traveling most of the time while he/she remains.
That's my 0.02. Others have their own opinions. Regardless, good job if you have offers from both.
