Astro Player offers plenty of futuristic good looks, but most of the features you want from it require payment. It's not terribly expensive compared to other player apps, but it doesn't show you enough to make you feel good about buying it. There are features that can help you fine-tune things, but audiophiles probably won't be too impressed.
When you first open the app, it notifies you to update it to the full, $3.95 version, to enable all the features. You'll see the same message when you try to access most of the app's features like bookmarking or gapless playback. The free version only gives you a few equalizer features and you are able to adjust the song's volume, treble, and bass. You are also able to add bookmarks and play Internet radio. The app supports DAR.fm and all you need to do is log in with your account details. Additionally, the app supports some streaming options in the form of podcasts, but you'll have to pay if you don't want to download them, manually. Playback speed cannot be adjusted in the free version, either. Same goes for fetching lyrics and missing album art from the Internet and on Wi-Fi. The app sometimes makes your audio jump whenever you look at a menu or change a feature, too. Astro Player's saving grace is the really cool layout on your tracks. Instead of traditional sliders, everything is controlled by circular gauges that are fun and smooth to use. The blue controls really shine on the app's jet black layout. You can change that in the skins menu, but it always looks fantastic and futuristic.
Sadly, most users don't care how good their music player looks. They care about getting the best bang for their buck. Keeping this in mind, the developers of Astro Player should have allowed users to test more of the app's features in the free version. If you're going to spring for a paid app, it should at least let you test how well its features work before you pay.