I can't really speak for the AMD platforms as I'm not that well versed in them so I will leave that for someone else to answer. As for Z77, it is the older Intel Ivy bridge compatible motherboard platform as compared to Z87 which is Intel's Haswell platform. In general, Z87 has about a 10% performance increase over Z77. All Z87 compatible CPUs include hyperthreading whereas the Z77 platform generally doesn't, unless you are going for an i&, in which case Hyperthreading is also a feature. Z87 CPUs also have onboard voltage regulators which help regulate the voltage going to the CPU making the chips more energy efficient.
Similar to the other response, I can't speak to the 990FX, but one advantage which might be big for you when comparing Z77 to Z87 is the number of SATA 3 ports. I have a Z77 socket and it has two SATA 6.0Gb/s ports. I have one SSD and one 7200 RPM hard drive (that runs 6.0Gb/s), so any other SATA device I end up adding will be limited to SATA 3.0Gb/s. If you plan to have a lot of hard drives and need the fastest transfer speeds on all of them, that might make a difference for you. Other than that, personally I'd go with whatever is cheaper (again, only considering the Z77 and Z87)