  We study the critical properties of three-dimensional O(N) models, for
N=2,3,4. Parameterizing the leading corrections-to-scaling for the $\eta$
exponent, we obtain a reliable infinite volume extrapolation, incompatible with
previous Monte Carlo values, but in agreement with $\epsilon$-expansions. We
also measure the critical exponent related with the tensorial magnetization as
well as the $\nu$ exponents and critical couplings.
