I happen to have both the aforementioned Seiko and Citizen watches, the latter being one of the Christmas presents my wife got me. Both are good sized and (so far) durable watches, and both look decent. The Seiko survived primary, most of advanced, Desert Talon, and WTI with not a scratch on it, and the Citizen survived TSA from New Bern, NC to Humacao, PR, and me wearing it the whole time I was on leave.
I would have to say that I like the Citizen a little bit better, due to the overall asthetics and GMT/second time zone function, but the Seiko does have an alarm, albeit a pretty hard to hear one. I think both are in similar price ranges, with the EcoDrive version of the Citizen being a little bit more pricey.