"Fast" charging is really slow charging, "regular" charging is even slower. A lithium battery can be charged at up to 1C (the capacity of the battery - IOW, if it's a 3250mAh battery, it can safely be charged at 3.25 Amps), but "fast" charging never goes that high. The limit is heat - if fast charging causes your battery to get hot (it varies among individual batteries), don't fast charge it.
A wireless charger adds some heat, but if you can grab the phone after an hour of charging and it's not uncomfortably hot, it's fine. A wireless charger saves the microUSB port, otherwise, there's not much difference. (I drop my phone on the wireless pad every night - it lasts most of the next day - and the battery is almost 4 years old.)