Mysql Sharding. Application Layer vs Mysql Layer

I am going to create shards in mysql table and I am stuck at a dileman whether to go for application layer sharding or let MySQL handle it. I mean, wether I should be figuring out which shard to go and query at application layer or pass on the query to the MySQL driver and let it decide. I read about some pros and cons of both here but I am unable to come up with a conclusion. My personal opinion is to go for the MySQL driver handling it. Open for discussion on this. Please share your views/experiences.