In a previous thread, "Lossy to Lossless" I reported that when I converted some old MP3s to Apples Lossless, they sounded better. I have not done any blind tests, but have converted about 50 of them and listened to most several times. I stand by my original claim. The MP3s I have converted to Apple Lossless have better definition and sound punchier.
If it sounds better to YOU, that's where it should end for YOU. Why would it make any difference what others think?
Responding for myself; I said the conversion MAY sound worse. You are asking the software to fill in all of the information that has been stripped of the file in the first place, without any access to that information. In doing so it basically makes up all the stuff that it's adding based upon what is already there in the highly compressed version. If you can live with that, and it sounds better to you, have at it.
I cannot imagine why anyone would do that unless the mp3 was all they had access to (as in a file straight off the Internet from iTunes). I don't buy any music that way. If there is music that interests me I'll buy the disc and rip the files in a lossless format. Disc space is cheap and my iPod holds 60gb of music so I find no reason to compromise the music for the minor convenience of downloading.
On another note pertinent to the original query; I'm pretty sure that WAV files do not support tagging so you may lose some of the metadata like album artwork in doing that conversion. Apple Lossless does support metadata so that would not be an issue. I'm not entirely clear on this issue so someone with more knowledge should chime in.