I wouldn't say screen printing is better than digital printing, just different. Screen printing is easier for us to produce hundreds of shirts featuring the same design - it's faster and more consistent. The digital printing allows for a greater variety of designs to be printed in a day, but it's much, much slower.
As far as the prints themselves, they should be comparable. Screen printed shirts may have more vibrancy (depending on the colors being printed) while digital printed shirts may have softer halftones/gradients.