Bowflex SelectTech 552 wins for convenience-focused users with its dial system and 52.5 lb max, while PowerBlock Elite USA 50 excels in durability with steel build and pin security. Bowflex adjustment speed beats PowerBlock by allowing changes in seconds versus 10-15 seconds per pin. PowerBlock longevity advantage shows in owner reports of 10+ years versus Bowflex needing earlier replacements.