I recently saw the GR OVA and loved it, and I saw the first episode of this TV series as well but didn't have the same feelings. Most of the people who like the GR OVA probably won't like this, it's different in everything from tone to setting and whatnot. If the OVA only used Daisaku and Robo from the original GR manga and merged all of Yokoyama's stories, this show will have the same feel, only it's eerie in the sense of it being a totally different universe.
Firstly, there's none of the retro look or high action feel, as in no orchestra. It's like a modern day version of GR. GR itself isn't any one robot, but a typology for big robots in general. Daisaku isn't the son of a Big Fire engineer, but just a normal (older) boy workinig on a coastal beach house. Ironically, with less responsibilities than twelve year old Daisaku, this older Daisaku seems a lot more mature.
I'll still watch GR, though. It gives be weird vibes considering the Robo universe I know from the OVA and the interpretation of the TV version, which might be more faithful to the original manga, I don't know.
I give full thanks to Anonymous for subbing it.