Anime Nerds seem to hate the taint from American influences on Japanese animation. Having been to Japan in 2008, I have seen how popular Lilo & Stitch franchise was in person. The local Disney Store was largely core Disney Characters (Mickey, Minnie, etc) and Stitch! stuff. In normal stores you could see Stitch and Angel (pink stitch) stuff regularly as well in those claw machines for stuffed animals. This show was popular and was more intended to appeal to Japanese culture than for Americans to watch it as an imported animation. Its unfair that Americans give this show any rating at all to behonest. Its so the Japanese can connect on a closer level to a hugely popular character by introducing this series that lasted three seasons while the original american cartoon series only lasted two series.
You can't even really compare the two except for how they were received by their respectable audiences.
That being said, if you're a real Lilo & Stitch fan you'll enjoy it for what it is, a spin off and a different take on a popular Disney character. Anime Hipsters will probably not enjoy.