SMD style is for surface mounting. Eighty percent of all tantalum capacitors are SMDs. Polymer electrolytic capacitors are characterized by low internal equivalent series resistances (ESR) and high ripple current ratings. Polymer electrolytic capacitors are mainly used in power supplies of integrated electronic circuits as buffer, and bypass and decoupling capacitors, especially in devices with flat or compact design. 

Solid electrolytes have electron conductivity.  As a result, solid electrolytic capacitors are more sensitive against voltages spikes or current surges. The oxide layer may be destroyed if the polarity of the applied voltage is reversed.

SMD style is for surface mounting. Eighty percent of all tantalum capacitors are SMDs. Solid electrolytes have electron conductivity.  Therefore solid electrolytic capacitors are more sensitive against voltages spikes or current surges. The oxide layer may be destroyed if the polarity of the applied voltage is reversed.

The main feature of modern non-solid (wet) tantalum electrolytic capacitors are their energy density compared with that of solid tantalum and wet aluminum electrolytic capacitors within the same temperature range. Due to their self-healing properties, the dielectric thickness can be formed with much lower safety margins and consequently with much thinner dielectric than for solid types, resulting in a higher CV value per volume unit. Additionally, wet tantalum capacitors are able to operate at voltages in excess of 100 V up to 630 V, have a relatively low ESR, and have the lowest leakage current of all electrolytic capacitors.