Microsoft tells us that there are now more than 18,000 Windows Phone 7 Mango apps to download from the Marketplace (and that figure may already be higher). It may not yet be in the six figure territory of the other two big mobile phone operating systems, but it's not a bad start for a system that's less than a year old.

And now third party multitasking is built in (if you can get it to work), you'll find that number steadily increasing. Also, with the likes of Nokia now on board, the number of Windows Phone 7 Mango handsets is set to explode – incentive enough for eager app developers.

The big thing for Microsoft here, again, is integration. It says that other operating systems have lots of apps that don't talk to each other, and that's what it's trying to correct. The live tile integration with third party software is one example of that now the APIs have been opened up.

At least it should be. We tried two of the big Twitter apps – Beezz and Seesmic – and neither of them had live updating of tiles when we had new tweets, mentions or DMs.

We assume this is because, although Windows Phone 7 Mango is now capable of such interactions, the third party apps will themselves need updating to work.

One of the things we found puzzling with the original Windows Phone 7 iteration was the inconsistency with the search button on the phone.

Sometimes it would open up a search on Bing and sometimes it would open up a search within an app, and you never knew which it would do until you pressed it.

Thankfully, Mango has fixed that and now, whenever you press the search key, no matter what app you're in, all you'll see is a Bing search screen. Should you wish to search, say, the Marketplace, or within an app, a separate on-screen search button is now provided.

Speaking of the Marketplace, it's had a slight refresh itself. Select an app or a game and you're presented with the information over multiple tabs (ie Reviews, Screenshots and so on).

It looks much better than it did before, where all information was just thrown onto one page, and is more consistent with the rest of the operating system.

Something we're big fans of in Marketplace is the 'try before you buy' option. We've long wished Apple would adopt this for its iPhone App Store, but fear we'll be waiting a long time. Android does offer refunds within 15 minutes, but it's often a pain to initiate.

This is a big plus for Microsoft – and we're extra glad when you look at the prices. We're not sure if Windows Phone 7 owners are a particularly wealthy lot, but you'll need to be to download some of these apps, which are priced way higher than their iOS contemporaries.

For example, Sonic the Hedgehog is £5.49 on Windows Phone 7 Mango, compared to £2.99 on iOS. Plants V Zombies comes in at £3.99, compared to £1.99, and Need for Speed Undercover is also £3.99 – a sizeable increase on the App Store's £1.79 pricetag.

We're sure that it could be argued that developers decide the price, not Microsoft, but considering this is a new operating system and one of its selling points is the wealth of apps, it's unfortunate for Microsoft that the devs seem to be pricing them so highly.

We're still irked that you can't reorganise apps, either – they're displayed alphabetically. But at least you're now provided with an on-screen search button so that you can jump to what you want if you have lots in there. Before, you had to manually scroll, which proved slightly tiresome.

You can also pin commonly used apps to your home screen as tiles, so all is not lost, although we'd like to be able to just hold down on the home screen and pin items to it that way (as you can with Android) rather than having to go into the app list, find the app and do it the long way round. Still, it only takes an extra few seconds, so that's not a deal breaker.

We'd also like to see app folders introduced like on iOS, but maybe that'll come in the next build.

When you download an app from the Marketplace, it now takes you to the main menu so you can see your app in the list, and a tap of the Back button takes you back to the Marketplace.

Before, it would install the app in the background but keep you in the Marketplace at the same time. It's a matter of personal preference whether you like this tweak or not.

There are also a few other small changes – for example, you can now send/accept/reject friend requests on X-Box live, and there are parental controls for the responsible among us.