Specs, while good indicators of overall performance, aren’t the full measure of a mic (or any audio device). The spec you linked to, is also incomplete. Most frequency responses that are accurate give a range and a tolerance (like 20Hz – 16KHz, plus or minus 3dB).
In general, mic quality and function are two factors, as different mics are intended for different applications. What will you be using the mic for? (Vocals, podcasting?) What are you recording (voice, or voice/instruments?) Will the mic be used in a quiet/controlled enviornment, or in exterior / field applications?
Best bet is to read opinions of users, through forums or other review sites.
The BLUE Snowball (I have it) is an okay mic, however, it seems to be a little lo-fi for anything beyond voice and podcasting-I wouldn’t recommend it for any music or critical recording applications.
Like camera lenses, mics are the thing that can make/break a recording, so being spendthrift about mic choices may not be in your best interest.
What are you using this for? What software are you using to record/edit (less important, but curious)?