Overall I had a good time reading it. As Charlock said it feels like rewatching the series (it actually made me feel like rewatching again) and it was quite interesting to see how the show was arranged and comparing it to the book, and also what was the original take of the author on one or another particular event.
Some of the statements that were left away in the show because of their descriptive nature were very interesting, in particular when it comes to detailing the history of a future that has yet to happen. It really shows the influence history books had on Tanaka's work. The characters seem to be very accurate in comparison with what the OVA did, at least the descriptions are. I quite had the feeling this was the script to the OVA, in the end. With a few mistakes and imperfections, but promising a gorgeous spectacle.

My main negative critique is about the writing style. I own another book, translated in french, from Tanaka (it's Souryuuden/dragon brother, who had 2 volumes edited in France before stopping) and it was much more fluid, and so was that fan translation of the LOGH novels (which goes a bit further than what's been published so far, if you can't wait to read the rest lol). I know the problem doesn't really come from Tanaka, who has a sober writing style in all cases, with a dash of humor that made me like characters such as Wenli even more (though I always liked him a lot).
I thought the translation was pretty bad in terms of fluidity, words repetition, ungraceful sentences, awkward even sometimes. I really hope this will be fixed in the next books because I found it quite unpleasant and I believe it could make so much damage to the success of this title, especially if they hope to seduce people who haven't watched the show first as well. I know Japanese is the worst language to translate in, say, english or french, but I'm sure they could do a better job on it...

That's about it. Looking forwards to the next issues~