I saw this a few years back and probably might watch it again at some point. I loved this anime, the second season, the movie, and the OVAs x) . The characters were livid and had real traits that made almost all of them feel human, they have reasons for joining into the ring, all different from each other. The main character in particular is outstanding on how he was a mere young boy who had no real social life and was too busy to do what most teens that time do. Then through his hard work and determination came to be one of the most respectable and skilled fighters in the sport.
Why was this anime so enjoyable? The music played at the right moments, the explanations during the battles helped build the tension from it now that you know how serious that injury actually is, and the characters made it all worthwhile to watch and experience. There's hilarious moments and really touching ones that are unforgettable and I highly recommend you try it out. You don't have to like boxing to watch to like this, believe me I wasn't really interested in the sport until I saw this. xD