No offence but GreenAddress is more trusted than yours and has been online for a long time. So personally, I would go for it.
https://greenaddress.it/We're still in our early stages so yes, we are not as well known in the space yet. However, we are legitimate. We just finished Boost.VC's accelerator (Tribe 5) and we won't we going anywhere so expect to see more of us
I also just want to point out that we are not a wallet provider like GreenAddress. We are an easy-to-use platform to create nLockTime transactions.
By the look of it, you want to 'lock' coins. Using nLockTime won't prevent coins from spending. You should use OP_CHECKLOCKTIMEVERIFY for improving safety. Anyway, current setup does
not help in preventing theft but it does help in scenarios like this because you can create an nLockTime transaction to spend from any address which will be included in a block later. Even if a person looses his/her private key, he/she can still get those coins. Only problem I can see is that we need to trust you with our money. I hope you will find a way to avoid it.
To be fair, GreenAddress is an online wallet but yours is more like a 'tool'.
