As an early adopter of Windows Phone 7, I was initially frustrated by the lack of text messaging alternatives like WhatsApp on the platform. Now that the platform has matured nicely, there are quite a few text messaging apps in the Marketplace.

Why text messaging apps? Instead of paying 5 cents per SMS, these apps send text messages using only a tiny amount of your monthly data quota. The group chat feature is also very popular, allowing users to chat with multiple friends in one thread.

Here are my picks for the top three text messaging apps on Windows Phone.

Messaging Hub (built-in)

No, this isn’t a trick entry. Windows Phone is an incredibly integrated platform, and the Messaging Hub is capable of more than just SMS once you add your Facebook and Windows Live accounts to your phone.

The Messaging Hub doubles as Facebook chat and Windows Live Messenger (WLM) client, and is better than individual apps because it threads all your messages from different places together. If you’re chatting with your friend on Facebook or WLM and he/she has to head out, switch easily to text and your messages all remain in the same thread.

However, there is no way to set separate online status for Facebook and WLM: appearing online on one platform means appearing on both. One could even say that the OS is overly integrated, resulting in the potential loss of privacy for those who like to go online selectively.

WhatsApp Messenger (free for first year)

WhatsApp for Windows Phone has neither the polish nor the responsiveness of its iOS and Android, but it is currently the best of the lot due to two main reasons: virtually everyone with a smartphone has WhatsApp, and its push notifications are the most reliable.

A messaging app is useless if none of your friends are using it, and this is WhatsApp’s biggest advantage: the app is available on iOS, Android, BlackBerry, Nokia Symbian, and even Nokia S40. In addition, WhatsApp’s push notification for new messages has the highest rate of arriving on time.

On the downside, the Windows Phone version of WhatsApp has to be the most sluggish of the lot. “Gen 2” devices such the Nokia Lumia 800 probably won’t have any problems, but on my LG Optimus 7, it takes roughly 5 seconds to load the app fully. Opening a message thread takes another 2 seconds.

Plus, somehow your friend’s name does not appear in group chats even if he/she is in your address book, which makes for eye-clawing frustration when trying to figure out who is saying what.

The user interface is, to put it nicely, very rough around the edges, and there is no customization at all to speak of. The message threads will simply use your Windows Phone theme. Plus, sending or saving videos is currently not supported.

Nonetheless, it’s many people’s go-to replacement for SMS, and I’m hopeful that future updates will solve these problems.

Kik Messenger (free)

Kik Messenger debuted on Windows Phone way before WhatsApp, and it’s more polished-looking than the latter. Loading time has significantly improved since the “Mango” version, and its in-app responsiveness is definitely better than WhatsApp.

It’s also available on a good number of platforms, including iOS, Android, Symbian and BlackBerry. I like Kik a lot, but not many people is on the platform, even though it’s completely free. My feeble attempts to convert some of my friends only entrenched them deeper into WhatsApp.

The worst part about Kik is probably its notifications. If you’re lucky, you get notified of new messages half an hour after it was actually sent. And if you’re unlucky, you can wait up till a few hours. If you’re really unlucky, the notifications don’t arrive at all. Needless to say, this is a huge impediment to its user experience, and makes the term “instant messaging” close to meaningless.

Plus, it doesn’t really import your address book like WhatsApp. When the apps discovers a fellow “Kikster” in your contacts, it automatically starts a thread telling you to start chatting by just replying to that thread. Is a list of contacts too much to ask?

eBuddy XMS (free)

Now we come to the newest kid on the block. Not a lot of people round this part of the world know that eBuddy is also into the mobile texting business, and they call it XMS. It’s available on iOS, Android, BlackBerry, and even MeeGo for you Nokia N9 toting folks.

Besides the basic text messaging, which XMS does moderately well, there is currently no support for sending or receiving multimedia.  The user experience, however, is more pleasant than WhatsApp. In fact, this is the only messaging app which lets Windows Phone users view those cute smileys iPhone users smugly send to each other.

While testing the app, the only glitch I could find was how texts have the tendency to get cut off, resulting in only half a message appearing with an ellipsis telling you there’s more to read. This can be fixed by quitting and re-launching the app. Also, group chat is not yet available.

As a newest kid on the block – eBuddy’s website doesn’t even list it as a download yet! – I can certainly be patient with this app. Until it gets more functionality and loses its beta vibe, judgment is reserved!