Deciding which type of external sign for your building is likely to depend on the type of business, location and the type of customer, client or visitor and market you operate in. Also what opportunity your location offers.
Is yours a prominent building and does it offer you the opportunity to promote your corporate identity. Are you looking to attract passing trade or simply to raise awareness of your brand?
You may not receive many visitors and wish simply wish to identify your premises.
Perhaps you receive important clients or prospective clients and need to make a corporate statement to reflect the quality of your product or service.