Don,
Monthly fee… like $14.99 you get assess to over ten million albums and thousands of internet channels. Yes, about the cost of one CD a month.
Streaming (assuming a good quality streamer) will sound the same as a red book CD or SACD if the same master and often HD versions may be available so the will sound better than a CD. On my system I can play a CD, stored file, streamed file and vinyl album they will sound the same. There is a bit of variability on the vinyl depending on what copy number it was on the master… later ones do not sound good.
I typically listen to full albums but you can search and find by albums, artists, songs or genre. There are lots of list (photos of album covers with artists and album name) of new releases and different kind of recommendations.
You can use an iPhone but you really want to use an iPad… you’ll start exploring a nearly infinite world of music quickly.
You also have a library… where any albums (or just songs) you like can be collected so you can easily find them. The streamer will go out and check and see if you have any albums on your network and copy them into your streamer if you want. There are playlists you can create of songs.
Whole new world… you want in.