I have and use the exact same model digital RS SPL meter and I am perfectly happy with it. If the variance in accuracy is +/- 2 db's that hasn't been enough to make me think that it doesn't work. Besides, I've never calibrated a system that didn't sound a lot better after calibrating than before.
The paper specs may say one thing but think about the use the meter will get in the real world. Does the +/- 2db's variance really matter? How will you gauge whether or not the device is measuring at -2 db's or + 2 db's? What you don't know won't hurt, atleast in this regard.
Doesn't it take 3 db's for the human ear to detect a change in SPL anyways?
For the price I'd say go for it.
FYI...it caps out at 126 db's (bro-in-law car stereo with TONS of distortion)