I owned this one:
8X Series, which is smaller than the preceding 7X series and larger than the current ones.
Seiko keep managing to make the GPS module smaller, so generally the newer ones are a bit more compact.
On the ludicrously expensive Astron rubber strap, next to a Citizen competitor.
Good points:
The GPS Astrons (Seiko has recently launched non-GPS Astrons, to which these comments do not apply) are built and finished to Grand Seiko levels. Dials, hands, case quality, crystal.
I say that as someone who has owned many, many GS in the past 15 years. The Astrons are superbly made.
GPS and solar, the most advanced and accurate autonomous wristwatch you can buy, and not have to stick on a charger every few days.
Engineering-wise, these are a marvel. That’s really why I bought these. I have an interest in state of the art wristwatches.
To take nothing away from my interest in exciting new bezel colours and lighter hairsprings even less affected by magnetism, but most of the actual horological rather than marketing innovation is taking place in Japan, not Switzerland. These Astrons are excellent examples of such innovation, beautifully engineered, at sensible prices.
Made in Japan. (The Citizen is made in China)
Less good points:
Heavy. Mine was in steel, and a lump. They do do versions in titanium. I'd shoot for one of those if possible. Perhaps the recent, smaller ones are more manageable.
The most painful rubber strap ever devised. Not sure what was wrong, but whichever way around I fitted it, it would cause insane pain on my wrist. I have never had this issue with any other watch, ever. Maybe the combination of strap (it's the correct model-specific one, about £200~) and the size of the watch, but it was unwearable.
I sold it eventually, mainly because it was uncomfortable to wear. The newer, smaller GPS ones (don't be fooled by the Astron-branded non-GPS ones, they are simply not in the same class) might be better.
TT