R2C2 repertoires have advantages and disadvantages compared to AIRR-seq repertoires: (A) CDR3 lengths, (B) isotype distribution, and (C) V segment usage for IGH repertoires are determined by AIRR-seq (top) and R2C2 (bottom). In C, different bar colors indicate different V segment alleles with gray indicating ambiguous allele calls. Red arrows indicate V segments where AIRR-seq fails to identify an allele unambiguously but R2C2 succeeds. Black arrows indicate rarely recombined V segments that AIRR-seq but not R2C2 detected.