Well, I will point out the advantages that both have:
Devour boi advantages: AP, Piercing Damage, Homing Attack, Danmaku, Shinsoo Barriers, Durability, Experience, Range Combat, Versatility, Reactive Power Level
Rubber boi advantages: Precog, Speed, can get faster as Snakeman during the fight, Accelerated Development, Regenerationn (?), Afterimage Creation
Where both might be comparable in stats and powers: Dura Negation (Goken and Piercing Technique could be comparable in their destructive power, but in general Baam's Dura Negation should be somewhat superior to Luffy's), CQC skills, Flight, Range, Stamina (Baam trained for three weeks in a mental plane and also "fought" against GoG for 1 month off-panel and Luffy is comparable if not superior to Ace and Jinbe, that could fight for straight 5 days)