Finite 't Hooft coupling corrections to multiple physical observables in strongly coupled N = 4 supersymmetric Yang-Mills plasma are examined, in an attempt to assess the stability of the expansion in inverse powers of the 't Hooft coupling lambda. Observables considered include thermodynamic quantities, transport coefficients, and quasinormal mode frequencies. Although large lambda expansions for quasinormal mode frequencies are notably less well behaved than the expansions of other quantities, we find that a partial resummation of higher order corrections can significantly reduce the sensitivity of the results to the value of lambda.