Here are some of the benefits of buying the best internal blu ray drives.
Connection: From eSATA to FireWire800 and FireWire 400to USB 2.0, there is a variety of connections. If you do not already have an eSATA card to your Mac, then a Blu-ray burner is not a good reason for you to do so.
Software: If what you want to do is to burn discs that you can watch via a Blu-ray player on your HD TV, you would need a software that is compatible with your Blu-ray burner. There are quite a few brands out there that provide you with these, like Roxio that offers the High-Def/Blu-ray Disc Plug-in for Toast. And as for Windows users, they have a software that allows them to watch Blu-ray movies on their laptops, but this capability is yet to reach the Mac OS X users.
Advantages: Even if you do not see yourself using Blu-ray technology any time soon, an external optical drive will be faster than the internal drive that you have installed in your PC. Having multiple optical drives makes duplicating optical media very convenient. Blu-ray media usually comes in 25 GB single-layer capacity or 50 GB dual-layer capacity, and this is a bit more storage than the 8.5 GB that you find on the standard dual-layer DVD.
Cost: Blu-ray burners are way more expensive than the standard DVD burners, but that cost is seeing a significant decrease. Many companies have cut the prices between the time they shipped their Blu-ray burning drives and the time they are used.