I'll assume that this is for In-game since you mentioned restarting Shield, so I'll just the pros and cons of both.
- Fine Ability in Blaze, it works fine.
- Great 116 Atk and 119 Spd.
- Fine typing in just Fire with only 3, albeit common weaknesses.
- Evolves relatively early at 16 and 35.
- Has access to Pyro Ball, U-Turn, Gunk Shot, Iron Head and Zen Headbutt, although all but Pyro Ball are by TR.
- Has advantages against Milo, Melonie, some of Hop's Team and parts of Leon's Team.
- Relatively eh bulk that won't survive much.
- Blaze is much worse than Libero.
- Little good level up moves that are bad until you get Pyro Ball and TRs.
- Weak against Nessa, Raihan, part of Leon's team.
- Fine abilities in Steadfast and Inner Focus
- Great Mixed Attacker and 90 Speed.
- Fighting/Steel is a great typing, only 3 Weaknesses.
- Fine moves in Meteor Mash, Aura Sphere, Dragon Pulse, Extreme Speed, Elemental Punches, Earthquake and a whole bunch of other moves.
- Advantages against Melonie, Opal, Bede, Marnie Piers, some of Hop's, Raihan's and Leon's Team.
- Worse Attacking and Speed stats than Cinderace
- 2 very common weaknesses.
- It is a pain to get and evolve.
- Weak against Kabu, Raihan and Leon.
Conclusion: I would go with Cinderace because Brute Force is the way to go. It has coverage moves that help it plow through teams and will help you in some major battles. It is also obtained much easier which is really beneficial. Both are usable, but Cinderace is better in my opinion.