Super #17 is Cyborg/Machine Mutant and Cell is a Biological Android. True is to Super 17 is very powerful, much cocky in this state. He was a penultimate Cyborg. His strengh, speed, powers, and techinques are twice as strong now. Even his body is twice as taller than before. Super 17 also gain special ablities like Ultra Sensitivity, Super 17 can sense the changes air and sound allows to detect even the slealthiest opponents making Super 17 very differcult to beat by his opponents. Also Super 17 has the ability to absorb energy into himself through a certain pose and add it to his own. He's made this his own type of absorption ability by not only regaining energy by stealing it, but by adding it to his maximum power and making him stronger. But it was a false term of Super 17's absorption because he extend his arms and legs outward to somewhat resemble a star and raise an invisible field capable of absorbing what seems like anything as long as he holds that pose. The limit on how much energy can be absorbed (if there is one) is unknown, as he even absorbed Goku's 10x Kamehameha meaning that Super 17 is sheiding himself in order to absorbed energy to get his energy to his maximum but not getting stronger. But It is at that point that Goku realizes Super #17's sole true weakness: when Super #17 absorbs energy, he is actually vulnerable to attack. Also Super 17's absorption does has a limit because when Android #18 fired her blast against 17, while she continues and goku ask her to stop because He thought that 17 would get stronger. Super 17 is moving his arms meanining their is one of a few chances that any opponent would beat 17 if they strong enough.His power does exceeds a that of Cells but not really stronger than him. Anyhow if Super 17 is defeated by goku with a sucidal help with 18, He don't exist anymore. Either a way he come back to his defused self in Hell.
Super Perfect Cell is really the Ultimate Android created by Dr. Gero. Despite it's power he has, He is cocky, but ruthless & very intelligent from Piccolo. Cell is also has the confidence and fighting smarts of Goku, along with the superior attitude and genius strategical mind of Vegeta, Frieza's conceitedness, and the Saiyan desire for battling strong opponents even his opponents is stronger than him. Unlike Super #17, Cell is able to psychologically manipulate those warriors and exploit their weaknesses to his advantage. His imperfect state is stronger than the original 17 as 16 does, even the Machine Mutant #17 is weaker than him. His powers will keep getting stronger each time to time even if he doesn't absorb his victims to gain his powers because of his Saiyan genes. Super 17 along with other absorption models has to get more energy to fight his opponents like 19 absorbs the energy of Goku & Vegeta, Dr. Gero absorbs the energy of Piccolo & Vegeta, Super 17 absorbs the energy of Super Saiyan 4 Goku, it's only a matter of time they use full-force against his/her opponents with their ki till they need to recharge by absorbing energy from their opponents compare to Cell has the ability to absorb any biological mass by stabbing his victims with his tail. This process, called "bio-extraction," drains all the organic mass out of the target from the inside out. This attack increases Cell's power, the exact amount depending on the victim's power level. Super 17 along with other absorption models, they could only absorb the energy of thier victims but cannot absorb their life-force to gain more energy like Cell did.
If Cell fought Super 17, this battle could be similar to Gohan vs Buu or Dabura vs Gohan. Cell could destroy 17 like this for Example: Cell uses this strategy to make another clone of himself, to shoot blast at him, then uses Ryu Ken, penetrated him to his middle body, shoots any kind of technique like Super beam Barrage or a kamehameha Barrage and I think that’s how he died.
Cell uses his physical more than ki basts like Vegeta making 17 beaten like last time in imperfect Cell saga. Super 17 lose & Cell won.