Regarding Bridgepoint's Pine Boost and Citrus Solv, both are 100% solvents, no water, not even added fragrances. The aroma comes from the ingredients naturally.
Pine does have a strong fragrance. We do not suggest using it as a spotter like Citrus Solv is used. However, diluted 1 ounce to a gallon as a booster for your prespray, both work very well and the pine is not over-powering.
Pine Sol may be harmful to some dogs, but I don't think it is because of the pine, it is other ingredients. Pine Sol smells like pine due to added fragrance, not due to the pine solvents.
Both pine solvent and d'limonene are terpenes. This is a class of solvents. All the terpenes are similar. So, one works just as effectively as the other. The differences are not in performance but in the fragrance and in the price. Pine Boost will run $9 to $10 a gallon less than Citrus Solv.