Despite the name, the Sidekick 4G isn't your grandmother's Sidekick of old (or your texting teen's either). The form factor remains the same, but the OS is now Android, and that's a good thing. This Sidekick is made by Samsung rather than Sharp, and it runs Android 2.2 Froyo with light customizations (way more toned down than TouchWiz).
The Sidekick 4G has HSPA+ 4G on T-Mobile's network, and it runs on a 1GHz Hummingbird CPU just like the Galaxy S line that includes the Vibrant. It's a peppy phone, and can handle Adobe Flash decently. The smartphone has a 3.5", 800 x 480 display (sorry, no Super AMOLED here since the Sidekick 4G will sell for only $99), WiFi with WiFi calling, GPS and a 3 megapixel autofocus rear camera and front VGA video chat camera that works with the included Qik video chat app.
Voice quality is very good, battery life is solid thanks to the 1500 mAh battery and relatively small display, and the keyboard is superb.
Here's our Sidekick 4G video review:
-------------------- Lisa Gade Editor in Chief, MobileTechReview
Video Review: Sidekick 4G Android Phone on T-Mobile