UltraSeven
I found that Ultraman Fans from USA love UltraSeven very much. I believe it got to do with the full broadcast of the series in US in the early days. And if I am not wrong, it is the first Ultraman show in US.
For me, as I mention, Ultraman Jack was actually the first Ultraman Series I watch back in my young day. Thank to RTM of Malaysia which broadcast the series and Singapore can receive the channel. Although at the time they were dub in Malay which we don't really know the story line, but who care, kids just enjoy when Ultraman appear.
UltraSeven, I got to watch him in action in the much later stage when Singapore broadcast his TV series in the mid 80s. But I actually first saw him in the Ultraman Jack Episode 18 where he hand Jack the Ultra Bracelet.
I'm not really a fan of Seven. He don't have the traditional look of Ultraman such as Silver costume with red strap, his eyes are joined, and his ultimate weapon is not the cross-armed firing ray but the so-call Ultra7-eye-slugger.
Being the 2nd Ultraman, Tsuburaya seem to think highly of him. This can be seen when they actually make new Video-to-home series of Ultra7 in mid 90s with the original "Ultra7 being" playing the role of Dan as what he did in those early production. And another reason for the new series could also Ultra7 is also one of the favorite Ultraman hero.