If you are ok with the fact that someone else can spend your coins.
They dont offer split key generation, I wouldnt use their service. I have a short step by step how split key gen works in my thread[1]. All legit services offer vanity generation like that.
[1]
https://bitcointalk.org/index.php?topic=1257817.0thank you they are one of the first results on google and also one of the best domain name.