The announcement is likely to split the fans right in the middle. To be fair, Lin was named as one of the potential directors - given by how much he has kept Fast and Furious franchise alive since he helmed Tokyo Drift in 2006. Lin is famous for his adrenaline pump and steady action handler, something that the Star Trek 3 may just needed. Besides that, his time at Fast and Furious franchise also shows that he is capable of handling big cast and budget.
If there is something you may need to worry, is probably he may not be well-versed with the whole Star Trek universe. Yes, he may spend time to devour into one, but concern if his vision may not sync with the one that J.J. Abrams already poured. If things go well, we should see Star Trek 3 to come into cinemas on May 2016, which will coincide with the universe's 50th anniversary.