It's very nice that you are here. （还好有你在这）对，很礼貌
lucky to have u / lucky you are here 也不错，很口语
还好有你 in good English 也可以说:
I'm so glad/happy that you're here （with me/by my side）= 还好你(在我身边)
It's so good to have you around! (= you're fun to be with)
We are lucky to have you or (It's) Great to have you here! 都意味着 = 还好有你的帮助和支持
I feel so happy because of you. （因为你我感到很幸福）不是这个意思，比如
说：You finally made it, I feel so happy because of you. = 你终于成功啦 我真的为你很开心
望采纳。。。
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