Microsoft is the latest tech giant said to be prototyping a smartwatch, according to a Wall Street Journal post earlier this month. Earlier this year, Samsung announced it was planning its own wristwatch-style computing device, and there have been rumors about an Apple iWatch and a Google smartwatch as well.

While we wait for the giants to play their hands, a number of Android-powered smartwatches are already on the market, and there’s at least one (Leikr) that runs Linux. The accompanying slideshow reveals devices of note, as well as two intriguing open source, Kickstarter-funded watches that don’t run a formal OS but offer hooks to Linux and Android: the MetaWatch Frame and the Pebble.

Last October, Gartner projected a $10 billion wearable smart electronics industry by 2016, defining the term to include smartwatches, fitness trackers in shoes, automatic insulin delivery devices, and even smart tattoos. Smartwatches face several obstacles, however, starting with the precipitous drop in wristwatch sales over the last decade. Even when watches were more popular, most smartwatch launches failed. These have included bulky products from Samsung and Microsoft, with the latter’s Spot watch discontinued in 2008.

About two years ago, Android smartwatches started appearing from vendors like WIMM, which last year retracted itself into a confidential relationship with an unknown partner. Miniaturization has resulted in sleeker designs for these newer smartwatches. Still, the question remains: Can a device with a 1-2 inch screen be efficiently touch-driven, or will we also need buttons, voice, and perhaps gesture commands?

A larger, related question is whether smartwatches can replace a smartphone, as is the goal of the mostly autonomous Google Glass eyewear computer. Or will the public instead prefer lower-cost, limited-function Bluetooth sync companions to a phone that one leaves in one’s pocket? Will fitness and health-monitoring dominate or will the focus be on social networking updates?

By the end of the year, we should see what some of the major tech vendors like Samsung and Apple have up their sleeves. By then we should have a better idea which way the category is going — or whether it is going anywhere at all. Click on the gallery link below for our slideshow of top seven smartwatches available now that are worth a closer look.