Generally, texts sent and received via Community are delivered faster than regular SMS! However, messages can sometimes take longer than expected due to delays in processing on a carrier by carrier basis.
Minor delays are expected from time to time and can happen due to a number of issues including; (but not limited to) a message being sent to a large group of recipients, messages being sent with large media files, and a general influx of messages being sent through a carrier network (similar to rush-hour traffic).