As auto overclocking goes, OC genie is one of the best. It's not as good as manual clocking as it tends to use too much voltage, and a fairly conservative clock speed. It does this because it doesn't test it's overclock at all, it just has a look at what hardware you have and applies some settings it knows will work.
There's no harm in tweaking the settings after running genie. Save what the OC button gives you in one of the profiles then go from there. You can almost always lower vcore a bit, or with sandy increase the multiplier a bit further, and if it goes wrong just revert back to the saved settings.