For a detailed discussion of amps to drive subs, see here.
Long story short:
Advantages are cost per watt, reliability, more reasonable warranty policies.
Disdvantages are looks, often lack of remote on/standby trigger, fan noise, sometimes gain-stage issues, may not fit in media cabinets designed for consumer audio gear. Also, some Class D pro amps may throw off enough RF interference to disrupt radio or OTA HDTV signals. (They are not required to have the same shielding that consumer products are.)