Of course the flow rates of performance depends on the operator (tested with very good results on Bouygues network with a simple map B & You), and trading volume. For temporary use, the current limits (Fall 2014) at a fair price, 3 GB or 5 GB / month, are quite sufficient.
Of course it is more expensive than the tethering via a smartphone, but the result and the capacity (number of simultaneous connections, into manageable options) are up. It is also a good alternative to the offers ready-sold some operators that force to take an expensive contract with commitment.