Do you mean a a Core i3? There are no E3 processors. Neither one of those processors is for a laptop. They are both desktop processors - if they were for laptops, they would have an M behind the name.
I guess it depends on what your friend is wanting to use his laptop to do. There is probably very little difference in the two, but click on the right side for "details" on each processor and see what is says there.
I didn't read this entire thread, but they discuss these two processors at Tom's Hardware... Compare Core i3 2120 and 3220
And if you want to wade through tons of benchmarks, here is another one... Core i3 2120 vs 3220