It really depends on it you're looking at it from the points of view of the consumer, the distribution, the production, or the artists?
From the artists point, it has made a few jump to massive success they couldn't have got before (eg Bieber)... but sadly, most of the most talented, lack the marketing skills to get known in this way.
It has also meant that artists have to try and make more from live gigs as the price on the music sales is less ... this is a significant change from the past where artists would make little from the tours and did them to promote album and merchandise sales.
From the production point, the popularity of auto-tume and drum machines has (IMHO) taken much of the heart and soul from music in favour of some pseudo-perfection. This is futher emphasised (though not a digital issue) but Glee, Idol, etc that just do covers ... making it tough for original acts.
Distribution is obviously the big change ... Apple's iTunes (after some court battles with The Beatles' Apple Music) and Youtube, have been big winners. But at the expense of some artists who would produce an album that told a story (Thick as a Brick or many Floyd or Who albums for example). While some argue that it allows lesser-known acts to release, unless they market (or are very lucky) they won't survive on the sales ... remember Apple gets most
For the consumer ... I think they'd be better off going to a local live music venue and really supporting those with the talent to perform live.
As a disclaimer, I look after the social media for this Sydney venue: https://www.facebook.com/BlueBeatLive
Happy to expand on these further if you like.