I much preferred Ashley to Sheva.
Ashley's good points:
- Ashley kept on getting kidnapped, and thus was absent for about half of the game in total.
- Ashley didn't fight with you, which meant you got to kill everything yourself.
- Ashley didn't have an annoying attitude.
- Ashley did whatever you ordered her to do without hesitation.
Ashley's bad points:
- Ashley died in one hit if you accidentally attacked her, even if it was with the knife. Although rare is the occasion when she got in your way.
- Ashley didn't exactly take enemy hits too well.
Sheva's good points:
- Sheva helped you out in dangerous situations, if you wasn't running off doing something stupid.
- You could dump all of the healing items and crappy weapons in Sheva's inventory system so that you can concentrate on using the Shotgun, Grenade Launcher, Rifle and Magnum, as well as Grenades once you have unlocked infinite ammo.
Sheva's bad points:
- Sheva heals you with a First Aid Spray or Green+Red Herb if you so much as prick your finger or stub your toe.
- Sheva steals your kills and ammo. The worst time where she steals your kill is if she fires a killing blow to an enemy a microsecond before you shoot, therefore leading you to waste your precious ammo.
- Sheva has an annoying, over-enthusiastic "We're partners to the end" attitude.
- If Sheva is on the Cover command, she uses nothing but her Handgun. If she is on the Attack command, she'll use the Machine Gun, but will run off somewhere and end up getting into trouble.
Sig and avatar by Ozzo. Thanks.