One doesn't always produce better smoke than the other. You can get the best results using either method if done right.
ive grown in both soil and hydro and i would say it doesnt matter. if u grow and cure your bud the right way the end product is always great.
soil will give you a more solid, sometimes earthy smoke. Hydro grows smoother, lighter smoke. Both reach max potential when cured properly, and even more significant difference is when you grow organic. You can taste multiple flavores, notes and tones. Growing with chems and synths really saddens the tones in the buds, but still grows steroidal medicine in some cases. Its ALL in the FLUSH and CURE. Some grower acquaintances I know of will only grow their OG strains in soil and will grow their sativas in hydro only.