Here is my sculpt of Jim Parsons (Sheldon from The Big Bang Theory)
Some technical info it took about 4 hours and is well over a million vertices.
So tell me what you think.
The likeness is close, but I wouldn’t have made the connection unless you told me. Somehow he looks older than Sheldon.
I like the style a lot, it looks almost like a marble sculpture. I’m not sure what your plans are for this, but it looks like it could be in a museum somewhere (maybe an aerospace and science museum hahaha).
It doesn’t make me think of him instantly, but I think I like it more than that - you should make it your own character 
Looks good =) Kinda has a cartoony feel to it
I would have to agree with Casio and Rabbit, it looks really good but it doesn’t really remind me of Sheldon. I think its a mixture of the length of the face and it’s very rare to see Sheldon smile lol. I would like to see you develop him into your own character because he already looks to have alot of personality to it 