In the past 12 months, we’ve seen the debut of several streaming music services, and while these have often be limited to running either on a website or smartphone, this week sees the launch of two similarly-named services that manage to bridge platforms.

First up is Rdio, a service created by the people who brought Skype to the world.

Like JB HiFi’s recently introduced streaming service, Rdio has a web streaming presence, but the offerings don’t stop there, with Rdio releasing apps for iPhone, Android, Windows Phone 7, and BlackBerry devices. Even the Apple iPad can jump on, as well as devices made by Sonos.

Rdio for iPad allows you to easily add albums to your mobile collection, ready to sync with your smartphone.

Similar to Sony’s all-you-can-eat streaming service “Music Unlimited” service, Rdio offers two subscription plans, a web specific plan for $8.90 per month with access available through the Rdio website, Mac and Windows apps.

If you decide to go mobile, you’ll need to upgrade to the $12.90 monthly plan, available for mobile devices, tablets, Sonos players, and even offline playback for smartphones.

The service launched this week with a seven-day trial service, giving you decent enough time to try before you buy.

More than smartphones, computers, and tablets, Rdio also supports devices made by Sonos.

We’ve been trying Rdio for the past day and have found that while the service has plenty of music to choose from, the apps could do with a bit of work. The service does offer a fairly wide selection of music, most of which can be found by searching, browsing new releases, or via the chart lists.

We’re a little confused about why there are no genre categories to search by, but the service does offer recommendations.

Rdio for Android

Offline playback works too, though Rdio doesn’t do it ridiculously quickly. At one point, we had only half an album synched, despite the app telling us it was all there.

Likewise, some songs and albums are listed as “not available”.  Given that it’s early days with the service, we suspect there are a few bugs to work out.

Then there’s the second service: Rara. Launched immediately after Rdio – and adopting a four-letter name beginning with “r” – this service is cross-platform too, but not nearly as versatile.

Rara offers web and mobile music playback, though at the moment, mobile options are limited to Android devices.

Rara's web presence.

The service seems to have the support of HP, with the computer company saying it will be pre-loaded on several locally released laptops, and coming soon to iOS and “other platforms”.

Like other services, Rara grabs its music from Universal, Sony, EMI, and Warner, effectively providing access to over 10 million tracks.

Music buffs will be keen to see that electronic and pop artist Imogen Heap has been taken up by Rara to work as an editor on the site, sitting on the company’s Music Advisory Board.

Sadly, Rara doesn’t offer a trial account, making it one of the few music services that lacks an introduction mechanism. Rara offers ad-free listening, provided you hook into the $0.99 price for the first three months and then pay $8 per month minimum afterwards.

Like Rdio, there’s an extra cost for using the mobile service, bringing it up to $12.99 monthly for having Rara’s music available to your mobile for offline use. At the time of publishing, Android Market doesn’t offer Rara locally, making it impossible for Australians to use on the go.

Australian Android cannot currently grab the Rara app.

We’re not sure about Rara yet, and certainly not having a trial or available mobile app doesn’t exactly entice us, though 99 cents isn’t a hard ask.

We do like cross-platform music services, but we’ll need to give both of these a more extended evaluation to assess their long-term appeal.

What do you think of subscription music streaming services like Rdio and Rara? Would you pay to trial a service? Do you even like the idea of music streaming, or would you prefer to own your music? Leave your thoughts in the comments section below.