The main disadvantage of course is that I have to carry around a small external drive should I want to access what's on it. I currently use it to store large games and backups from my iPhone and iPad (which can be sizeable) but other things such as photos would work too.

So I found a reasonably fast external SSD to plug into one of the never used thunderbolt ports (a LaCIE Rugged Thunderbolt 512GB). Not finding a consensus on the web whether these newer MacBooks SSD's are upgradable, I decided not to risk it. I purchased it with 512GB but in hindsight, I should have purchased it with 1TB. I took the easy way out to expand the SSD disk storage on my MacBook Pro 15' Retina (late 2013). I'm sure you've heard the joke: 'There are 10 kinds of people in the world those who understand binary, and those who don't.'

So, OWC's 480 GB is the same size as OWC's 512 GB unit. Your response DID clear up my misunderstanding of why OWC's SSD maxes out at 480 GB they're using the more conservative estimate of size (base 2 vs base 10), contrasting with Apple's measurement rubric.

My reply to 'helpme05' was intended to suggest to him that there may BE such a product from OWC in the future, because iFixIt's teardown of the newest MacBook Pros shows that the SSD still plugs into a (mecahnically and logically different from that on the 2012 and early 2013 machines) motherboard socket. Of course, that's not relevant for the OP, who has a late 2013 MacBook Pro and wants a bigger SSD. I may not have been clear enough in my post OWCs SSDs will NOT work in the late 2013 MacBook Pros (they've clarified their website product description to make that abundantly clear) the newest MacBook Pros use PCIe controllers, both for the SSD interface and for the SDXC slot the 2012 and early 2013 MacBook Pros use SATA the two are NOT interchangeable, and OWC doesn't make ANY SSD cards that will work in the newest MacBook Pros (yet).

Macbook pro 2013 retina ssd