I currently use an old 1HP craftsman, with a 4" hose. It's not bad, but I bit more suction wouldn't hurt. It's hard to beat the Harbor Freight 2HP unit when it's on sale for $150 or less.
I wouldn't want to use a Shopvac, due to the noise factor.
The shoe design is critical for good dust collection. You'll see all different materials used for a skirt, but imo, a good brush is the best method. For best results, the brush needs to form a "seal" to the part or table. Any gaps between the brush and table will allow chips to get out, regardless of how much suction you have. Chips are thrown at very high velocities, and the brush is needed to contain them within the range of the vacuums suction.
Keep in mind that some operations are bound to let dust and chips escape, no matter what you do. But a good shoe design will allow you to cut sheet materials with zero airborne dust, and very few particles left on the table.