Both are are equally good.
but when we factor in the after sales support in Msia (if that is part of your concern too), then i would say go for Seiko. Apart from Thong Sia, plenty of places are capable to service and obtain parts easily.
with Citizen, you will vomit blood. Calls went unanswered, Facebook and emails un-replied. i even went to their office in Subang Jaya, during office hours on a workday, guess what? they're bloody closed and nobody answers the door.
This, coming from owner of 3 citizen watches. do you think will i consider another citizen again even if it is an extremely good watch? big fat NO.