Wherever possible, we use direct or 1-hop connections. This means that you are getting the highest quality SMS delivery available on the market.
Generally, you can expect messages to arrive in a matter of seconds; an SMS message typically takes about 10 seconds to arrive on a handset. This may vary based on the recipient country (going up to 30 seconds) and depends on whether the receiving mobile number is reachable and in good signal coverage.
As there are a lot of factors and variables that can impact delivery times, it's hard to give a specific number.