A 'strong scent' recommendation is hard to answer when there are different ways a fragrance could be determined as 'strong'
If you are seeking that instant 'blast' of a scent then you want to look for a fragrance with alot of 'top notes'. Since top notes are the first you smell these are the ones that will give that quick impact that most people look for with a home fragrance. Alot of perfume/aftershaves in stores are designed with 'quick impact' in mind, because they want to sell them so they need to make a good first impression. As such you may find perfume/aftershave or other 'dupes' are what you would prefer. As those generally have the most 'top notes' in the make up. However, with these 'top note' heavy scents it's important to note that with all fragrances whilst the 'top notes' are the first impression notes they are also the first to evaporate off within a scent. Leaving the middle and base notes to carry the rest of the way. If you are someone who defines a 'strong scent' as one that lasts a while then you want to focus on the 'base notes' in a fragrance as these are the ones that provide longevity and are last to evaporate away.
A complex fragrance features a multi-layered make up. Usually this results in a scent which has well balanced notes in each layer and will provide both a strong throw aswell as being long lasting.