"Better" is too subjective of a word to use here. There are certainly phones with different specs, but even looking a the 3 major complaints (camera, processor and sd card), it's not as simple as picking a device with a higher number. It's all about how the software interacts with the hardware. The Nexus devices have a history of maximizing this interaction to significantly increase the overall speed of the device, as compared to others with higher numbers. Then there is the issues of software updates. Nothing will ever beat a Nexus in this area. Optimized software will typically outperform the next 1 or 2 generations of hardware. This means that even when quad cores actually hit the marketplace (as opposed to just being talked about), the Nexus will still outperform it until the next generation of Android is released that utilizes those quad cores.
Having said this, if you need to have that 8 mp camera, or that 1.5 ghz processor, get whatever the latest device is that has it. I'm sure it will be a great phone (most all of them are), and I'm also sure the Nexus will smoke it performance wise.