I know this is an old topic...but I thought I'd weigh in. I use music 1 for my Internet Station (use Selector at my real "radio" job) and I like it alot. I don't use a ton of rules, and I don't do an awful lot of dayparting. It does a very nice job at visualizing rotations for the categories, and it's easy to drag and drop and move stuff around the clock each hour. It's not as easy to go find a song you want to insert into the playlist at times, as you have to sometimes pop open another window to find what you want.
You can set it up to work like Selector, where it schedules the whole day, or use the "interactive" scheduling feature that stops at various rule problems and let's you choose what song to plug in as you go along. Since on the web I'm programming a pop station that plays rock, alternative, pop, hip hop, gold and unsigned groups--genre seperation is important--and while it does a nice job of following my rules, I tend to do a lot of massaging anyway since my musical balance of those genres aren't always the same. One of the features of the "interactive" scheduling, in theory, is once you get your rules where you want them, you should only have to fix your rule violations--not mess with moving stuff along.
I've had a few conversations with Steve Warren, the radio consultant who designed it, and I get the feeling he's very willing to work with clients to get the rules and features the way you want it so it works perfectly. I've never bothered to do that, since, look--my web station is my hobby--and it doesn't take me long to massage what I need, and mess around with the rules etc. when I need to adjust some of the settings to make it work better.
If my company was looking to make a switch from Selector, I'd certainly recomend it as a program that's worth a good look.
www.reactradio.com