Oh, the player repeatedly crashed and the Message Center pop-ups were annoying too, although I did eventually disable them. Later, the proprietary license was a (no pun intended) real turn-off for me.
But why did you switch to RealPlayer from Winamp?
Because RealPlayer was better. And that's not saying much.
Well, I wasn't a big music listener; I really used RP at first because its browser mode was the only browser on my WinME computer that worked. Then I started listening to music and browsing the web, and I thought 'I don't need Winamp! This program is cooler! It even has a dancing sheep!' After RealPlayer got on my nerves, and I got a new computer, I used Win Media Player instead and completely forgot about Winamp. :)
I, for one, even bought a "real player gold" license. Ha!