Microsoft has caught laptop-slash-tablet contenders by surprise with its upcoming Surface Book, but Lenovo isn't backing down easily with its Yoga 900. How will the Yoga 900 fare against the beast that is Surface Book?

Straight off the bat, let's start with the dimensions. The Yoga 900 comes in at 0.59 inches thin, whereas the Surface Book comes in at 0.51 to 0.90 inches thick, depending on when it's being used as a laptop or not. Microsoft's flagship weighs a bit more at 3.34 pounds, and Lenovo's weighs less at 2.8 pounds. But the Surface Book is fitted with a 13.5-inch display (3000 x 2000, 267 ppi), which is slightly larger than the Yoga 900's 13.3-inch display (3200 x 1800 QHD+, 276 ppi) with 300 nit brightness.

Now it's time to tackle the specs. Both devices are packed with sixth-generation Intel Core chipsets, ranging from the i5 for the starter models to the i7 for the top ones. While Lenovo managed to go toe-to-toe against Microsoft in the CPU department, the Redmond tech firm takes the cake for including a dedicated Nvidia GeForce GPU for its later variants in the keyboard.

Both are running Windows 10, but Microsoft offers a free 30-day trial for Windows 10 Pro on the Surface Book.

Regarding RAM, both devices also range from 8 GB to 16 GB, and about the storage, the Yoga 900 ranges from 256 GB SSD to 512 GB SSD, whereas the Surface Book ranges from 128 GB SSD to 1 TB SSD.

For the cameras, Yoga 900 sports a 1 MP front camera, and the Surface Book is fitted with a 5 MP front camera and an 8 MP rear camera.

In terms of audio, Lenovo's hybrid device is crammed with a 2.5W JBL stereo and features Dolby Audio Premium, blasting sound from all sides. Microsoft's flagship is loaded with a front-facing Dolby audio system and dual microphones on its front and rear.

Next up, let's compare the ports. Yoga 900 wins over the Surface Book on this one simply because it has a USB 3.0 Type-C along with two USB 3.0 Type-A. The Surface Book comes with only two USB 3.0 Type-A ports. Also, Yoga 900 comes with a 4-in-1 card reader for SD, MMC, SDXC and SDHC. On the other hand, Surface Book is equipped with a full-size SD card reader.

For connectivity, they are on equal grounds, having a Bluetooth 4.0 and an 802.11ac Wi-Fi.

Now for the all-important battery performance. Lenovo boasts that the Yoga 900 can go for nine hours with continuous video playback, assuming that it's not streaming. But Microsoft tops that with 12 hours of battery life in the same situation.

For their unique features, let's start with Lenovo's. The Yoga 900 is fitted with the same but improved watch band hinge used in the Yoga 3 Pro, meaning it can do a 360-degree rotation. Compared to earlier models, it also gets an improved cooling technology, which makes the cooling system run more efficiently and quietly. However, the tablet can't be detached from the keyboard.

Moving forward to Microsoft's, the Surface Book comes with a Surface Pen. The tablet can be detached from the keyboard by pressing a specific button on the keyboard and can be reattached facing away from the keyboard to go into tablet mode. Also, the Surface Book has two batteries: one in the tablet and one in the keyboard.

Microsoft really went all out, pricing the Surface Book from $1,499 to $3,199. Lenovo wins in terms of price tags, setting the Yoga 900 from $1,199 to $1,499. And when it comes to colors, the Surface Book is limited to Magnesium Silver, whereas the Yoga 900 comes in Clementine Orange, Platinum Silver and Champagne Gold.

Here's a side-by-side comparison.