Rate constants and kinetic isotope effects are calculated for the CH3 + H-2 --> CH4 + H reaction by two theoretical methods: variational transition state theory with semiclassical corrections for tunneling and an approximate (linearized) semiclassical initial-value representation method, recently proposed by H. Wang, X. Sun, W.H. Miller [J. Chem. Phys. 108 (1998) 9726]. The theoretical results agree well with each other and with the experimental data in the temperature range 500-1500 K. For high temperatures, the differences between the two theoretical rate constants arise from the more accurate treatment of dividing surface recrossings by Miller's method.