--The review contains spoilers--
If you have already seen the anime adaptation to Ginga Nagareboshi Gin, then the first 13 of the 18 volumes will be very similar. Only a few scenes being taken out of the anime for time purposes. But there are only minor differences. Beyond volume 13, a large arc takes place that the anime never touched on.
The wolf arc. Ginga Nagareboshi Gin gets a solid ending by Gohei's funeral and an adult Gin saying his last good-byes to his old master. It was a perfect ending to a pretty perfect story. There were battles and deaths and it is saddening that Toei
Animation never made it through the whole series.
Most of the dogs were shown in the anime, except for a few minor ones such as Kisaragi's sons who Chibi met before they are killed by Akakabuto's solders and Beth, a perverted dog who wanted to make Cross his slave.
The wolves were exclusive to the manga and some were given their own versions of the Battouga. When many of the wolves died, they always did it with a cause, whether it was suicide or dying in battle to protect Gin and his pack, each death was a important one.
Though a few of the characters' name are quite ridiculous: Pink Dragon, Thunder Wolf, Mountain Bison, Black Snake, White Tiger, Thousand Dragon; the list could go on and on.
Anyway, the art in Ginga Nagareboshi Gin is really good though could be better. The animals were sometimes drawn much better than the human characters, and the violent battle scenes to were portrayed to sow the most blood as possbile. Even with the vast (And I do mean vast) amount of characters in the manga, each one had their own distinctions between each other to tell them apart easily. Yoshihiro did an excellent job with this series.
Enjoyment would be low if you can't read Japanese. And unfortunately, it seems that there will never be an officially licensed English version.
Overall, if you're a fan of action, dogs, and adventure stories of nearly epic proportions, you'll love Ginga Nagareboshi Gin. But as I said, there is no official English version. (However, GingaSite.net is providing a fan translation)
If you ever take the chance, start reading Ginga Nagareboshi Gin. I'm sure you won't be disappointed. Ginga Nagerboshi Gin was Yoshihiro's most popular manga series and it fully deserves that title.