While both are 4g LTE phones Motorola Droid Bionic has a larger screen 4.3" when compared with the Atrix's 4.0" the camera in Bionic is 8 megapixel with 1080p HD video capture when compared with Atrix's 5.0 MP with dual LED flash. Cpu in Atrix is Nvidia tegra 2 (1Ghz dual core) with Geforce ULP functioning as GPU.And in Bionic its a Texas Instruments 1Ghz OMAP4430 chip with a PowerVR SGX540 GPU @ 304 MHz which is a good GPU.Both the devices have pros and cons but the better phone in budget will be Atrix. Though I suggest to wait if you are not in a hurry there are devices soon to launch which will manage the battery in 4g LTE phones as the phones being manufactured currently still need some battery benchmarks to conquer.