Intel's new Haswell CPUs bring a good 25% performance improvement to the integrated graphics core of the socket 1150 platform. Motherboard vendors can pick an even faster graphics core called "Iris", but it's only for CPUs that will be soldered to the motherboard.
Our testing not only sees that Intel has improved performance, but the drivers were also stable, and I didn't notice any rendering errors, or similar issues. When looking at performance, the HD Graphics 4600 solution is just way too slow for any serious gaming, even at 1280x800. I picked "High" quality settings for each game before starting the test, and was apparently too optimistic. Framerates are nowhere near playable, but I could imagine some games to be playable if you pick the absolute lowest settings and play at low resolutions, which certainly won't deliver the right PC-gaming experience.
Compared to other low-end graphics solutions, we see performance about 25% slower than AMD's APUs, but Intel is catching up quickly, and AMD hasn't improved at all with their latest Richland processors.
Bottom line: If you want to do serious gaming, don't expect Intel's Integrated solution to provide a decent experience. Rather, save money on the CPU and spend it on a real graphics card. Even a $100 Radeon HD 7750 or a used card out of the last five years will significantly improve framerates. You will, on the other hand, be fine with an integrated solution if all you use your PC for is YouTube, Facebook, office productivity, and browser gaming.