For lossless, use the search function.
One thing about m-ch analogs from a bdp is that if the track is 5.1 that's all you'll get. You won't be able to matrix. With optical, that's something that you would get to enjoy with a 7.1 system.
You can connect both then. So 7.1 lossless track, enjoy that natively, and with a 5.1, you can choose either 5.1 lossless, or 7.1 lossy matrixed. You can also compare which sounds better. Perhaps no difference to you.
You can't qualitatively compare lossy vs lossless unless you have a particular soundtrack. If the master is no good, then lossy will give you no-good. Just like with video, if the master is bad, 1080p is not going to create a miracle.
Please use the search function for basic questions. You can search either any particular:
whether specific to any poster. results can be chosen both as either threads or posts. thank you.