According to his profile, he is the ultimate man-made warrior due to being the ultimate machine mutant and ultimate android combined.
Due to possessing both components of the ultimate Machine Mutant and Android, Cell 17 is truly is one of the most powerful warriors. Dragon Ball Fusions lists Cell 17 as an S-rank fighter, listing him as around the same level of strength as Super Saiyan 4Goku or Super Saiyan 4 Vegeta, though extremely powerful G-rank warriors such as VegitoBlue and Super Saiyan 4 Gogeta outclass him by a wide margin.
Metamo-Ring - As an EX-Fusion, Cell 17 wears a single Metamo-Ring on his left arm which was formed by Cell and 17's two Metamo-Ring fusing along with them. Cell 17 can remain fused as long as he wears it and can defuse at will by removing it.
Cell 17's appearance seems to resemble more of Super 17 instead of Android 17 and is even said to be the combination of the ultimate android (Cell) and the ultimate machine mutant (Super 17), although it is by fusing Android 17 and Cell that Cell 17 is created.
Cell 17's appearance resembling Super 17 may be due to the fact that one of Perfect Cell's absorption components is already Android 17, and Perfect Cell fusing with Android 17 would be the same amount of Android 17s that fuse into Super 17.