compare learners for multiclass classification

Hello forum members,

I'm looking for a method to compare several learners for multiclass classification. Until now I have only worked with binominal label, now there are four classes. So the ROC-Comparison can't be used. The only other comparison method I know is to test all learners with X-Validation and compare the classification accuracies.
Does someone know a better method?
My data has one special attribute: the polynominal label (4 classes), 125 regular attributes and 102587 examples.

Thank you for reading!
Kind regards,
Deborah