Are there any hard drive differences between this and the Mid-2013?

As to what SSD is compatible with the newer '14 model.

Apple has been tweaking the SSD firmware on the M.2 SSD's so far they have three different firmware revs across the MacBook Pro models. It also turns out each rev of firmware is only compatible with a given model so one can't switch what looks like the exact same M.2 module between the different systems. Talk about confusion!

So far we have stayed away from trying to figure this all out. We where hoping Apple (and the other system manufactures) would have stabilized things by now so the SSD's would be standardized like SATA drives as well as be more upgradable and interoperable.

I think your best bet here is to talk with Transcend sales directly and also make sure you can return it if it doesn't work.

Their Web site does not list it as workable. You have a MacBookPro11,2 or MacBookPro11,3 so I would say it likely isn't. Sorry ;-{