Itunes match is excellent.
it scans your library, and matches the songs it knows against apples massive database.
once thats done you can then download high quality DRM free versions of the matched tracks
you can also listen to your entire library on your iphone, ipad and appletv

but if you dont have good metadata (song names, album names, etc) then itunes match doesnt fix that.
it keeps your original metadata.

it would be nice if there was an option in itunes to fix the broken metadata, but there isnt (yet)

there is, however, a thirdparty app (there are probably loads of them) that I have tried and it seems to do the job.

itunes match helper will scan your itunes library and for any song that has the status ‘matched aac audio file’ and download the metadata from itunes and fix ll your broken tracks!