Arjun supposed to have dark complexion and his age was said to be more than 70 years old.
In terms of looks - Navi Bhangu had dark complexion did a decent job he had good screen presence and warrior look.He played Brihannala very well in Suryaputra Karn series. His costumes were also good.
Shaheer Sheikh didn't look like Arjuna. He look like lover boy and chocolate boy. So I didn't like his role as Arjuna. However his comedy timings and interactions with other actors in the character is enjoyable to watch. So he is good Arjuna in terms of comedy timings and romantic timings.
In terms of dialogue delivery and acting skills -Firoz Khan did excellent job as Arjuna or Partha but his costumes were worst. Infact all of BR Chopra's serials had worst costumes. They look like cardboards rather than metal armors.