iTunes Plus upgrades
I used the iTunes Plus update service to update four tracks that I bought in DRM format that have since been updated to better quality/non-DRM versions. To update a DRM track to non-DRM costs 50 cents. I irritates the hell out of me that I have to pay to update my already purchased tracks to a format that costs the same if bought directly (both iTunes and iTunes Plus tracks cost $1.69 each).
I suppose it indicates that iTunes values the cost of a "purchase" at 50 cents. I wonder if bands get a royalty when a user upgrades?
Converting iTunes Plus tracks
The biggest benefit of iTunes Plus tracks is that you can right click on them and convert to WAV. No hacking, no real-time ripping, no irritation. The quality is better, but it's the convenience of not having to climb barbed wire fences just to use the files I've bought that I love.
Track quality
I've often found tracks with audio flaws in them. They're very minor, and usually I've blamed my method for conversion to WAV, but I've found similar problems in iTunes Plus files. The kinds of tracks I buy are so obscure that it could just be the source material and lack of time spent on quality assurance of the source files. But still... it makes me wish for CD. With the way the format is presented, you just never know if it was the source material, or if Apple (or the record company, or the artist) stuffed up in some way converting the file.
They don't have everything
Ultimately this is my biggest issue with iTunes. I'll use the web to search for music, discover an artist, and find they're not on iTunes. Or only some of their albums are. Or maybe just a single track from a compilation.
At times I've tried other Australian digital music companies (Telstra BigPond Music, Destra) to find tracks that aren't on iTunes, but they're never there either.
Usually these tracks are on the American services. Either the US iTunes, or AmazonMP3 or whatever. But I'm not allowed to use them because of where I live.
I can use eMusic (I think?) but it's a subscription service (US$10 a month for 30 song downloads per month) but I'm not ready to sign up to a service like that. I think it's excellent value, but I'm not ready to commit to spending time every month finding 30 songs I want. Particularly as all of their music is indie.
Catalog quality
The iTunes catalog needs work on the more obscure stuff. I accidentally bought the DRM versions of some songs, even though there was an iTunes Plus version of the album (which had slightly different spelling).
The fact the shop has some in DRM and some not is irritating in itself. I bought a compilation track recently in DRM format, only to find it on another compilation without DRM. In their catalog, technically they're a different track, but in reality, they have thousands of tracks duplicated for this reason.
iTunes will never be the perfect song/album database I want it to be, but it would be fantastic if it was.
A single place to go where you could search for a song, and if you like it (and if it is available), you could buy it, would be brilliant. No duplicates, all version differences explained. No confusion on formats.
Convenience
iTunes is convenient. It's far easier and cheaper to search for and buy a track on iTunes that it is to either buy the real CD, or even to pirate it (ignoring single track P2P software, which I refuse to use anymore).
But for whole albums they have a long way to go... mainly on price. I'd still prefer to pay the "premium" to buy a real CD than I would to buy digital versions of all the tracks.
I think the market would support single tracks being much more expensive than whole albums.
I'd love to see albums on iTunes drop to $5, with single tracks dropping to $1... but I'd even be happy to see then stay at $1.69 if album prices dropped.