SMS Gateway Price and Feature Comparison

Recently I have been developing a SMS application for a customer in Rockhampton and have spent significant time researching SMS Gateways for my customer in attempting to select the most appropriate one for his application.  Many great SMS Gateways don’t suitably work in Australia, which is dissapointing.  We have ended up selecting Tropo –

Here is a comparison table of my research thus far.  The table shows best price, which is sometimes only possible with bulk credit purchases.  It also shows if the service has an API, supports MMS and supports 2 way messaging.  Some of the Gateways which do support 2 way message have limited features with this. 

SMS Gateway API MMS In Out  Best Price (US & Canada) x x x  $  0.01 (International) x x x  $  0.01 (UK) x x x x  $  0.05 (International) x x x x  $  0.03 (Australia) x x x  $  0.06  x x  $  0.03 x x  $  0.03 x x x x  ? (German) x x x  $  0.02 (Australia) x x x  $  0.04