A must watch for anyone interested in the mecha genre I'd say.
If you are in for the enjoyment of a good anime, then the movies are a far better option. It's a shame the last one has been delayed for so long, eta 2020.
For more mechas and better feels give Eureka Seven a try. Beautiful animation for its time, similar style to other classics, and a great OST. It's a bit long, however.
There is also a sequel (Eureka Seven AO) that kind of shits on the first part and thus many dislike it. I think it can be enjoyed if you treat it as an unrelated production.