If you are a small business, working with a specialist online marketing agency Singapore in most businesses, this means that a bigger business will get priority. On the other hand, if you have a big business, then any agency focusing on small business does not have you manpower or resources to serve you adequately.
Note that you are able to understand the average size of those professions. You are working on the agency you are considering. Reference chain is important, however, it is not possible to evaluate an online marketing agency. This is probably the best customer service of the marketing agency.