Pirat You made three points. Let's review them.
Pirat In any case, I think that new users will be difficult.
Fair point, it's quite difficult to trust a new developer but talking to him and figuring out stuff is also a way. If you still have doubts then it's your money and you can always deny after talk.
Pirat I know that this is second engine Toby, and he does it almost in javascript
Toby's first engine (as you say) was esoTalk which was also built on PHP. I don't know from where you are getting your facts.
Pirat but even my friend could not understand this engine and he programs in PHP
Just because your friend couldn't understand doesn't mean that you can judge other person's intellect correctly on this matter.
Look it's your money and you can hire anyone you like. But don't be rude to people who are trying to reach you. That's like the golden rule of community.