The only problem that's even possible is that if one of the chargers can't supply as much current as the other device wants, it'll take longer to charge that device.
Charging cellphones is just about universal these days - a ~5 Volt (some chargers put out up to 5.2 Volts - that's fine) microUSB charger. Any charger will charge any device with a microUSB charging port. (A few tablets - mostly no-name cheapies - have round charging jacks, so the plug won't fit, so you can't make a mistake, they just won't work with normal chargers.)