We've had the Helio Ocean for a few hours now, so we thought it'd be a good time to go over the core features and answer a few of your questions while we were at it.
First off, the core features. The dual sliding works just as well as we saw back at CTIA. The sliding is nice an crisp and gives you a great "clack" sound as you slide. Very satisfying to do over, and over, and over again, but annoying to the people around you. The screen flip time is negligible—especially comapred to Windows Mobile phones.
Then, the software.
There's loads of "presence" stuff in here. Besides having AIM, Yahoo, and MSN for IMing, there's Yahoo Mail, AOL Mail, Hotmail, GMail, Helio Mail and Earthlink Mail as well. For the IMing part, you can integrate your contact's IM information into their contact entry and see whether they're online just by searching for their name from the front screen. Very convenient.
As for IMing itself, we're going to call this a desktop-class IM client. It's loads better than the stuff we get on Windows Mobile. However, we do wish it had word completion and suggestions, which would make it even easier to type on.
The standard menus are there (standard for Helio phones, that is), but the browser is improved as well as having an instant search-as-soon-as-you-type from the front screen. Convenient.
Helio's GPS/Google Maps and Buddy Beacon are also here, a favorite from the Helio Drift so you can locate both your friends and yourself.
The screen itself is super bright, and we had to turn down the brightness just so we could capture it on video (coming later).
Now for your questions: yes, you can browse while IMing, but once you exit the browser to go to your IM, your browser shuts down. So it's not exactly like multi-tasking, but you won't be disconnected from your IM either.
Yes, the keyboard is great to use. They're more like the Sidekick 3 than the HTC type of large keys, which is great for people who are migrating.
We'll have more impressions later in the day as well.