I have a Sony Ericsson Walkman phone. Which it has to be said has better SQ (Sound Quality) than most phones. But then its a "Walkman" phone, so it should be. But most phones do not have as good SQ as the Sony "Walkman" phones. Lots of MP3 players has poor sound quality, but IMO the Sony phone isn't as good as the best MP3 players. Of course if you only listen to low bitrate music and though bad earphones, and in a noisy enviroment its not going to make much difference. If you more particular about SQ you might not like it, but it ok. However most other phones I've listened to sound terrible.
http://www.google.ie/search?hl=en&c...esnum=0&ct=result&cd=1&q=proprietary+&spell=1
My main gripes are more practical. Most phones don't let you use decent earphones. They have a propietarty connector so you have to listen to the supplied headset which is usually dire. Mind you if you are happy with the miserable earphones that come with most MP3 players, then you probably won't notice. My phone has an adapter so you can 3.5mm earphones. But the lead on this adapter is waaay too long, its about 2ft long, so I have to wrap and tie this up to make it shorter. Which is a pain. You also have to remember to carry the adapter with you, and they are not cheap if you lose it. The navigation menus are a bit of pain on my phone, it doesn't handle compilations intelligently, you can only browse by Artist or as a sub set of Artists, All Albums. Mine ignores track numbers and thus doesn't play albums in the correct play order. From what I've seen, most people can't figure out (on phones or MP3 players) these menus, or tagging, so give up, don't use tags properly and just leave their phones/mp3 players on shuffle.
Using the MP3 on a phone, and too a lesser extent the phone, kills the battery very quickly. I would usually get about 4~5 days out of my phone. Use it as a MP3 player and I'd be lucky to get 2 days out of it. Most phones have worst battery life than the Sonys, in my experience. Usually a day at most using it for music.
File transfers over the supplied serial cable, Bluetooth etc are painfully slow. If you've only a small capacity on the phone, you end up synching quite a lot. Its far faster to take the memory card out of the phone and put it in a card reader. But even then its still far slower than transfers to a MP3 player. Some phones, like the Sony have easy access to the Memory card, but many require you practically disassemble the phone to access it. If you only have a handful of tracks of low bitrarte (small size) then this might be not much of an issue. But in general getting stuff on and off a phone isn't as easy or as quick as MP3 player.
In general I find it hander to carry a small flash MP3 player with my phone. Better battery life, sounds better, easier controls, handles tags much better. Faster transfers. Getting more capacity cheaper then buying a memory card for the phone. My phone gains better battery life. I only have to charge the phone one a week, and the MP3 player once every 2 to 3 weeks.
Mind you I'm a bit more serious about my music than most. Having said all that, in a pinch I'll use the phone for music/radio and if you are not too demanding its quite handy and sounds ok.