With its sleek design, flashy menus, haptic feedback, and full-on 3G access, this touchscreen delight for Sprint users looks to be one of the strongest iPhone competitors to date. Read on for my hands-on impressions.

Announced Tuesday here at CTIA, the Instinct (set for release in mid-June) looks like a virtual clone of the iPhone, but it delivers many of the features missing from Apple’s red-hot handset, including 3G access for speedy browsing and downloads, a replaceable battery, expandable memory, and haptic feedback for the touchscreen - that is, a slight vibration each time you tap the screen. This key feature is sorely missing on the iPhone.

I got an early, hands-on look at the Instinct a couple of weeks ago in New York, and I have to say, it’s the most impressive iPhone contender I’ve seen yet-or at least until I try out LG’s touchscreen Vu, which is also set to debut here at CTIA.

The Instinct certainly scores in the looks department, with its smooth, jet-black face (à la the iPhone) and 3-inch display, along with three keys-Back, Home, and Call-just beneath.

Measuring 4.6″ by 2.2″ by 0.49″, the Instinct is a tad narrower but a bit thicker than the iPhone, and it’s also a bit lighter, weighing in at 4.4 ounces.

The Instinct’s sleek, animated touch interface looks promising, if still a bit rough-and-ready. The unit I tried was still in the testing stage, so I’ll hold off on direct iPhone comparisons until I’ve seen a final device.

Still, a lot of the UI innovations that I love on the iPhone are right here. Navigating on the touchscreen was a pleasure, and I liked the roulette wheel-like scrolling through long lists of items.

Another ace up the Instinct’s sleeve is its access to Sprint’s 3G “EV-DO Rev. A” data network, which means speedy Web surfing, full-track downloads from the Sprint Music Store (which got a badly needed makeover for the Instinct), video clips from Sprint TV, and the ability to tether the phone to your laptop for on-the-road Net access.

More good stuff: GPS navigation combined with voice commands, allowing you to bark “Go pizza” to the Instinct and get turn-by-turn directions to the nearest slice.

And here’s a feature that travelers will love: the Instinct’s removable battery, good for swapping out during, say, coast-to-coast flights. The iPhone’s battery is-as many have groused about before-sealed in its shell, meaning that if it runs out of juice and you’re nowhere near an AC outlet, you’re out of luck.

Rounding out the Instinct’s features are microSD memory expansion (up to 8GB), a 2MP camera, stereo Bluetooth, and a media manager for sideloading music and videos.

Good stuff, although I should point out that the Instinct’s Web browser (or at least the version I saw) looked pretty clunky compared to the iPhone’s, and the Instinct’s POP/IMAP/Outlook Web access messaging won’t be able to match the iPhone’s upcoming support for Microsoft Exchange servers. There’s also the iPhone’s potential as a software platform to consider, now that the iPhone SDK is out in the wild.

And of course, by the time the Instinct arrives in Sprint stores (sometime in mid-June), we may well have a new 3G iPhone on our hands.

No definitive word on pricing for the Instinct quite yet, although I’m told it could be in the $200-250 range.

So, what do you think? Do we have an iPhone killer in our midst?