I'm slowly becoming a strong advocate for the Eco-Drive technology. Why? Usability.
What do we all expect from a watch, except accuracy and reliability? We expect it to be hassle-free. So is the case with this Citizen, model BJ9130-05E. It's an analog watch, therefore you can expect the usual corrections needed for a watch of the kind: if you live in a country with daylight saving time (DST) you know that you have to change the local time twice a year (you never change the GMT hand, naturally, since the UTC time is, by definition, fixed). And since it has also a calendar you have, naturally, to correct, sometimes, the date at the end of the months. Besides that, this watch, in the mighty words of the HAL 9000 computer, is "...by any practical definition of the words, foolproof and incapable of error.". Also, trusting on a machine powered by solar energy, it will never, ever, needs manual winding, wrist winding or a change of battery. Citizen, however, is - thankfully - not alone in this ecological approach to watchmaking. You'll find similar technologies in Casio (Though Solar) and in Seiko (Kinetic), just to name the most popular ones.
As far as I could see, while searching for a cheap dual-time watch, this is the most practical and less expensive on the market.
The GMT (or dual-time watches) are direct descendants of the marine chronometers existing on board ships for centuries. The purpose of these high precision watches was to "keep" aboard the Greenwich Mean Time (GMT) and, by comparing it with the local meridian time of the ship, to give the longitude of her actual position. Curiously, the traditional marine chronometers display twelve hours instead of twenty-four, which is kinda funny if we think about the duration of a day.
So this technology migrated from sea to land, and with the advent of modern air voyages now it makes sense that the normal traveling people, and not just the professional mariners, need to have at a certain moment, simultaneously, the time in two different zones.
It's up to you to decide how to organize that dual information. If you travel often, let's say between two countries, it makes sense to have the hour, minute and seconds hands on the homeland time and the twenty-four hour hand giving the time for the visited nation.
Me? I'm traditional. So, faithful to my nautical background, I always keep the 24-hour hand on GMT time. And I change the local time (according to DST variation) twice per year.
Regarding time setting, let's give the word to "rationaltime", the moderator of the German Watches Forum, of the website "forums.watchuseek.com":
"...The movement is the Citizen B876 Eco-Drive GMT module, which has been used in other Citizen analog GMT watches over several years. The orange 24 hour hand is set together with the minute hand when time keeping is stopped and the time is set. The 12 hour hand and date are linked, and set with the time keeping still running. Some people refer to this as "true GMT". The hour hand jumps in one hour increments when the crown is turned...”.
Enough said. Enjoy it.
The Citizen Eco-Drive GMT 180 WR100 World Timer GMT, model nº BJ9130-05E (about 100 UK pounds on Amazon) photographed on its case. Arguably one of the best dual-time watches money can buy.